Thank you Gilbertd
I transferred the complete loom, resistor and all from my other car, now used for spares.
My compressor clutch pulls in and stays in for some time. The small compressor pipe gets really hot and it just appears to me it might build up pressure so much that the trinary pressure switch is activated and disconnects power to the clutch. It is at that point I switch the motor off.
I will have to get a gauge set to confirm that is happening.

Yes, in my hook up to power the relay 10, as the temp of the evaporator rose to that 5/6 degrees the clutch did re engage. I thought I had seen that somewhere but I have been looking up a lot of info and couldn't find it again. Thanks Just got to find out what is wrong that the HEVAC it's not doing the job for me.

No very early on in P38 ownership I realized the operation of the button. I only used it in the post to indicate that I could switch the system on/off and the clutch worked.

https://lr4x4.com/topic/109433-p38-hevac-sensors-replacementmodification/ is the site I found out about the 30kohm thermistor.
Using an infra red thermometer on the heater pipe the reading was pretty well the same as the Naoncom figure.

I was looking at a set of gauges offered by a car air con company here in Australia for AU$40 so will check for correct fittings. Thanks

I had to stop working on the air con for more important things in life, however now attempting to get it sorted.
My auto electrician is 55km away and while he is helpful, 1997 P38's don't form any part of his business.

All the work I have done so far has solved problems along the way but still I haven't been totally successful. So I have posted a long list of what I have done so far in the hope I can gain a bit more knowledge to reach the final goal of cold air in my car.
Compressor changed for one that was known to be operational.
Compressor clutch clearance adjusted to low side of specifications.
Land Rover wiring loom for early models added
Giving power to the compressor via a relay. No 10 in the fuse/relay box. 12.7 volts when last tested.
The known problem of corroded multi pin plug/socket cut out & cables soldered. Right side foot well.
Any connectors relevant to the air con operation cleaned.
Nanocom now showing YES to grant. So it’s talking to the engine module.

Aspirator Sensor for cabin temp. Removed from dashboard. Fan & sensor cleaned out, removed fluff.
Ambient Temp Sensor made using 10Kohm thermistor, piece of plastic conduit and thermal epoxy.
Heater Pipe Temp Sensor made using 30Kohm thermistor original plastic housing clip and thermal epoxy.
Receiver Drier Renewed.
Pressure Switch 2 (single switch) Renewed.

Took it into town to get Re gassed. Had to supply 12v to relay 10 to get the charge of 1200grms of gas into the system. Yes i know not the1250 grms but he stopped at 1200

HEVAC module still refused to activate Relay 10.
However supplying 12 volts to the relay proved the system was working … nice cold air.
But on a trial drive evaporator temp going down to 1,5 to 2 degrees, compressor clutch dropped out and fans activated. Evaporator temp went up and operation continued.

However I was warned that bypassing the HEVAC could possibly cause problems.
So the wiring bypass was removed.

Now just Fitted :-
Pressure Switch 1 (the trinary switch)
Evaporator Sensor Renewed.
On engine start up system would not operate the compressor clutch. So switched off.

Disconnected the battery for 15 minutes.

On re connection and start up HEVAC recognized everything and the on / off switch on the HEVAC will switch the compressor clutch on / off and there is no “book” symbol on the HEVAC panel, so its not reporting any problems.

Nanocom showing only one fault.
“32 Compressor Clutch Control Circuit Open Or Shorted to Ground”
Fault Type = Current.

Yet there is 12.7 volts at the compressor. Clutch can be operated using HEVAC ON/OFF button.
Compressor clutch clearance adjusted to low side of specifications. Done at the beginning of workings.

The smaller pipe out of the compressor gets very hot, larger pipe more at ambient temperature.
So NO cold air.

Blockage ??? Expansion Valve ???
I don’t have any gauges so guess I will have to arrange a trip into to town to my auto electrician.

Does anybody have any further ideas before I book in to my auto electrician?

It's been some time since I had the brake problem.
Dealing with my wife's health problems and I needed time to be spend on the Defender, then computer problems.

Time became available a week ago to organize the brain to make a simple check on the ABS pump motor. Applied 12 volt to it and it didn't work.
Took the unit off the spares car and brakes and lights all fixed, car operational again.

Now just need to get the air con operational.

Thank you Gilbertd. It will take me a bit of time to try and take all of your excellent description.

Gilbertd thank you again.
Yes I noticed the different pin size so swapped it with the one on the parts car. On the bench 12v across 85/86 both relays I could be hear the contacts pull in.
Maxi fuse 3 live on both sides. RL17 pin 30 live. Ign on 2 RL17 pin86 live. RL17 pin 85 good earth.

Ign still on 2 at C184R, taken off the ABS sensor, pins 1 & 5 have good earth, pin 2 live (something to do with RL17 coil?), pin 3 live (something to do with ABS ECU ?)
pin 4 nothing. Connecting C184R back on to the sensor resulted in power at the + terminal to the pump and its earth was good.

I have tried the gentle tapping with a small hammer on the sensor and the pump motor, a suggestion I have seen on the net.

Prior to this problem, that I have caused, the brakes were excellent. Brake fluid just renewed and new brake pads. Pedal only had to be moved slightly down with little effort to provide very positive controlled braking.

Any Ideas on what I have done?

Thanks Gilbertd
I have been trying to fathom out the operation of the ac system and do not put myself forward as an expert on the matter my only real source is the manual and info from Marty.

Am I seeing it wrongly.
The pin 7 should be activated by the yes/no grant and that is not happening so hence my "external" 12v source the the relay 10. So yes I think the Hevac is faulty.
However doesn't that signal only activate relay 10 that then sends the power down to the trinary switch that with the the gas pressure activates the clutch.
Then isn't it the two pressure switches that govern the fan operation I quote a post from marty who in turn is quoting figures from the manual.

https://www.rangerovers.net/threads/ac-update.52810/

marty_nz

Dual pressure switch (trinary sensor) under 17psi or over 435psi, and the switch will be open circuit
Between 35psi and 305psi, the switch will be closed circuit (A/C compressor will kick in)

AJ comment So ”open circuit” means it will cut the power to the clutch thus saving compressor damage.

The single pressure switch is the one that turns the fans on/off to start with:
Under 189psi, the switch will be open circuit
Over 247psi, the switch will be closed circuit (turn the fans on)

If the pressure switch is over 247psi, but the trinary switch is between 247psi and 305psi, then the fans will run at slow speed
If the pressure switch is over 247psi, and the trinary switch is over 305psi, then the fans will run at fast speed.

On my vehicle static tests the Nanocom showed the evaporator temp going down to 1 degree and the pressure would have risen, the clutch dropped out and the temp rose to 10/12 deg area and the clutch pulling back in to continue the supply of cold air at the dash vents.
At the same time the fans came on slow as the pressure in the system increased and then to high. Once the system went back to the evaporator temp in the 10/12 deg region the fans switched off.

So is there some other input the causes the Hevac to cut the power at pin 7 that I have not seen in the wiring diagrams?

Andrew

Thanks for the reply.
Yes once again I failed to get all my facts in the post.
All fuses have been checked and the relays that are marked ABS in the main fuse box have been changed to ones known to be okay.
The diagnostic port I have changed for one from the spares car that I thought was okay, but maybe I should have purchased a new one and soldered that in place.

I haven't got rid of the connector in the left foot well, I think some items go through there from the diagnostic port.

While I was trying to get the air con working on my 1997 model I had the fuse/relay box loose and propped up at an angle to see underneath connections.
I had a wire I was experimenting with, it shouldn’t have been live, but may be it was and it touched the body metal and big spark, all happened so quickly … shouldn’t have been working so late in the day.

Turned ignition key on to find nothing working in instrument area and not all working in the centre console.

Next morning found a major fuse in the engine area fuse/relay box blown …. One of the 60amp ones only remember that as the plastic was dark and difficult to see without a light shining through it. So replaced it and all appeared to be back to normal in the cabin, I went on my way and finally got the air con working.

Sunday I went to go out for a drive, now with working air con. Started up and only now realized the ABS pump was not operating and the hand brake light remained on even when released. A very short drive and the light did not go out as it usually does.

So I am left with ABS, H/brake, TC lights on and no ABS pump operating.
The only check I have done is to prove there is 12v main supply to the pump.

O yes there is one other thing, no matter which section I look at in the Nanocom I get the same notation …..
“unable to start communication with” ( eg engine).

Once again I would appreciate any ideas as to where I can look.

Andrew

Hello All
My air con problems I hope are fixed.

Hevac recording -40 deg and snow flake symbol from faulty ambient temperature sensor and heater pipe sensor recording silly temperatures according to my infra red temperature gun. Both these fixed using thermistors as in this post https://lr4x4.com/topic/109433-p38-hevac-sensors-replacementmodification/

Living outside of a major city purchasing parts and then mounting them has taken a bit of time. I used this to mount them…
https://mgchemicals.com/products/adhesives/thermally-conductive-adhesives/high-thermal-conductivity-adhesive/ 8329TCS – Thermal Adhesive.

I found the a/c grant was actually varying “Yes / NO” and after checking connections mentioned in this set of above posts the problem was at the Hevac. Connector C246 on right side of Hevac has, on my car, very little free play in the wiring loom over the years of this unit being taken out and moved about it had put strain on this connector. It carries the wires for the grant. The only solution I came up with at the moment was to install the connector with a thin piece of plastic card so that it was a tight fit.

As stated earlier, TBS wiring loom was fitted and compressor clutch gap had been adjusted to the lowest specification. The connector in the right side foot well had been removed and wires soldered. The correct amount of gas was finally in the system. And still no air con unless the relay 10 terminals 30 / 87 were bridged. The earth 85 was good. There was still no 12 volt to relay 10 86 pin.

At connector C244 on the Hevac the black and yellow wire on pin 7 was dead. This wire is to relay 10 pin 86. Other power wires into the unit were okay.

I took relay 10 out of the fuse box made up wires from pins 30, 87 and 85 back into the fuse box. Then for now, took a 12v feed from the accessory plug/socket inside the car through a fuse and on/off switch ran it through the firewall to relay 10 pin 86.

12v to pin 86, engine on, cold air virtually straight away. Nanocom readings all correct. A couple of 45 minute test runs static in the carport have shown operation of slow condenser fan followed by fast fans, evaporator temp going down low and compressor cutting out and back in on the rise of the temp.

I went to go for a run and realized I have another problem ….. but not air con so that will be in a new post trying to seek help with that !!!!!!

Andrew

Hello All
Short post to my original post No 1.
Feel like an idiot not understanding Ebay it was in the end simply me not pushing the right buttons.
Thank you to those who suggested I contact https://www.ebay.co.uk/itm/404025564146 I finally sent one fob to him.
He reconditioned the fob in a matter of days the postal services took the most amount of time getting the fob from Australia to UK and back.

Totally recommend this chap my car now locks and unlocks perfectly using the fob buttons.

Hello All
Sorry for the long post I just don't seem to be able to shorten down the problems explanation.

I managed to get my auto elec to put 1200 gms in the air con system, the pressures, according to him, were high, so the last 50 gms is still in their machine. Persuaded him to have the motor running but nothing got the compressor clutch to pull in. He pulled out the relay 10 and put a jump lead across 30 / 87 so the clutch pulled in to complete the refill.

Once that was done and relay replaced, (clutch dropped out) I noticed the HEVAC screen had on left a snow flake then EXT – 40c. He agreed that the ambient sensor could now be the problem. Nanocom reckoned it had changed its mind now NO grant.

Today I took the ambient sensor off the 1998 spares car (air con was working 6 months ago) easy to remove from in front of condenser. Managed to get socket off the in the air duct sensor and plugged the replacement into it and left it hanging in the left foot well, probably not the most ideal place.

Running on a fast idle nothing to start with HEVAC on low/low showing snow flake EXT -40c. then snow flake stayed on the whole time but NO EXT -40c and a/c grant YES system started blowing cold air from dash vents.
With a day time temp of 30 deg c.
It took nearly 30 minutes to see on the Nanocom

Ambient temp 11c it stayed at 11c the whole time
Aspirator temp 24c it started on 26c
Evaporator temp 5c it started on 18c at 5c the clutch was operating in / out at times (as it should I believe)
Heater core stayed at 80c after warming up.

Dash centre vent temp 4c.
Then clutch dropped out and EXT-40 joined the still visible snow flake and warm air again. The snow flake is obviously a problem as it is only to show possibility of road ice.
I switched off motor and left it for another time.

The ambient sensor, mounted in front of condenser, must have been working in the other car as the air con was operational.
Maybe if I removed it from the wheel well, mounted it out the front and ran two wires back to the socket in the cabin?
I can’t see that would upset the HEVAC.
Looking at RAVE diagram for 1997 there is UO wire out of HEVAC to sensor and WB wire back no connectors. Sensor in air vent. Wires not shown in 12 pin plug LH side.
1999 diagram shows same colour wires going via 14 pin connector in behind LH wheel well panel. Sensor is out the front of car.

It appears that the sensor is no longer available. So has anybody found a usable replacement? Is my problem the sensor or something else as well?

I made up my own loom for my 1954 Citroen, made up loom from fire wall to lights for my 1974 Citroen Dyane, worked on my 1998 Defender, but the electrics of my P38 are in another world.
Thank you
Andrew

Thank you Pete12345 and Gilbertd for the comments.
I found the connector you said about while I have been trying to understand the wiring diagrams and due to their location I checked them. They looked clean but sprayed them with contact cleaner.

Sprayed contact cleaner on every plug and socket I could find.

Having seen various people having problems with the 18 way connector under RH kick panel I have solder jointed all the wires. Sorry I forgot to mention that.
I will also do the same with the connector under the LH panel soon.

Yes I spotted the compressor clutch gap that a is mentioned a lot and adjusted the clearance, that is remover the shims and got a gap of to 0.35 mm.
( 0.35 to 0.65mm is listed as the accepted range ) Forgot to mention that as well Sorry.

A couple of months ago I booked it in with my very helpful auto elec chap he gassed it up and declared that there was an electrical problem that I would have to find as the compressor clutch was not pulling in.

Hence the fitting of the TBS kit from my parts car. That's when I got the similar funny behavior that romanrob said in post 7 .

Confident that my problem would be fixed I got from the UK a new receiver drier and pressure switch 2 (the single one) and changed the trinary switch 1 from the parts car, It was working only 6 months ago, and booked into my auto elec chap.
He gassed it up and declared that the problem was still there ! ! !
Thus my post 9 above.
After Gilbertd's post 10 I am now more informed about gas requirements. My auto elec chap has written on the sticker on the car "gas 700gms"
Why didn't I look in the manual ? ? It clearly states 1250 gms.

So I will be phoning on Monday for an appointment to get the air con gassed ! ! ! ! But will that fix the non working air con ? ? As the saying goes watch this space.

I have tagged onto this posting as I have a very similar problem to romanrob post 7.

I fitted the loom as in TB 0010 from my now spares 1998 model.

I knew there wasn’t a full charge of gas in the system from attempts to get working a/c a couple of months ago, before the loom was fitted so I just put a jumper lead across
Trinary switch socket 1 black/yellow and 2 white/light green.

I had seen in the post 9 that it was on the 3rd starting the compressor clutch engaged … well so did mine, so downed tools for the day.
The next morning started engine …. No clutch engagement.
I thought it might be because not enough gas on the system so booked it in at my auto electrician.

He evacuated the system and fitted the new receiver drier and pressure switch 2 single switch that I supplied and re gassed it. Only to tell me the compressor clutch was not engaging so I had an electrical fault.

I have been trying to get my old fashioned brain to sort it out.
If I jumper across relay 10 socket 30 and 87 the clutch pulls in and cold (not freezing) air starts to come out of the dashboard vents. But there is no power at 86 to pull the relay contacts in.

Very late Friday afternoon I noticed a sticker in the engine area saying 700 grams was put in the system. Just looking at info on the net last night I realized that is not a full charge, the manual advised me it should be 1250 gms.

Is there a chance that with a full charge of gas the feed to relay 10 would be there to pull the compressor clutch in ?? My electrician does’t work weekends)

Nanocom lists the only fault is 6 RH blend motor current fault.
It also says YES to the grant.

Again any ideas would be most appreciated
Andrew

I will add my thanks to the work done by gordonjcp post 1628. I have no idea of what he was talking about, and being computer stuff I prefer to not know. Hopefully rrpub will keep rolling along for some years as it has been a great source of information for me.

Like nigelbb my next comment is not, what I have done today, but what I have done over the past week and a half.
Living in Australia I couldn’t drop round to get Gilbertd’s opinion about the same noise in the front end of Bimbo, my red P38. However my long suffering wife told me to replace the either one or both front wheel bearings.
My previous green P38 is now a parts donor, and I knew that its previous owner had recently renewed both front hubs and as I found out an added bonus of two near new brake discs. They came off just by removing the holding screw so obviously not been on the car for long. I was able to remove axles and hubs with no dramas.
So to removing the units from Bimbo, to be short in description, it was all seized and took me a bloody long time.
Two new axle seals, a set of brake pads and all the good parts installed …… no noise, thanks given to wife for correct diagnosis.

I laughed at nigelbb’s comment on the roundabout, I too suffered the same thoughts …… the dual exhaust does sound nice!!

My work continued on to remove the official LR air con fix harness that I found was on the green car, and install it on the red car. Green car also supplied a near new air con compressor. My auto electrician is yet to install new receiver drier and 2 pin switch and recharge the system and he is confident I will have an operating air con system. Just as well as the day time temperatures are up to low 30’s C already so looks like a hot summer is on the way.

Tomorrow I start on removing foot well multi pin plug/sockets with soldered joints.

Andrew

Hello
Gilbertd
I live in the state of Queensland Australia
The 'Contact the seller' option was not operational, nothing could be written in the box.
Aggravated Insult gave me stupid information and I couldn't get rid of its comments.

Lpgc
Thanks for all the info and I have sent an email to the "private" address and he may see that during your day time over there, so I will wait for any reply there might be.

My shed contains four registered vehicles :-
1954 Citroen Big 15, owned since 1984 but only fully restored on the road for 12 years.
1974 Citroen Dyane owned on the road for 42 years. It has seen a lot of Australia, 3rd time round the clock.
1998 LR Defender 130 300Tdi with self built camper body owned for 15 years used to make forays out to
enjoy this great island. It took over from the Dyane.
And for the last 4 years I have been a P38 owner. First one was a cheap one, then last year I purchased a better looking car but not so good in other respects.
Gilbertd and others were a great help early on when I was trying to deal with petrol in the oil.
At 76 year old and taking on a P38 my long suffering wife declared me mad. But she still helped me do a brake fluid change today.

Thanks Andrew

Thank you to you both for the contact address on Ebay for getting the key fob refurbished.

I read all the information on his listing and went ahead .... Buy now ... paid my money .... got the receipt ..... got the email from Ebay.
That email, according to the seller, was supposed to contain the postal address for me to post my key fob over to UK. Of course it it did contain the address.

So I enter the murky Ebay world where no human being exists to try and contact the seller. (I could not find contact information by looking on the net).

Well you enter the even less helpful, if that is possible, world of AI. This grubby little ** doesn't want me to contact the seller. So I haven't

I canceled the order and now wait for 3 days to get a refund. Or just maybe a message from the seller.

I wonder if the seller is even aware that he maybe loosing business due to Ebay Aggravated Insult.

Thank you Gilbertd for the quick reply

To be honest I have never been aware of any red light on the fob when inserting the key into the ignition.

I wasn’t very clear when I said :-
“Tried to sync key fob as I have done in the past ….no flashing red light this time …. no sync.”

What I actually tried was exactly what you suggested.
That procedure has never failed to sync the key fobs for me on the two P38s I have owned in the past 4 years.

There has now been a change since my last post.
Late this afternoon I thought I would try the procedure again.

The regularly used key fob when turned in lock and unlock pressing the buttons, gave no flashing red light.
But did lock/unlock manually.

However when I tried the spare key, turned to lock, button pressed no red light and locked manually, but turn to unlock, button pressed and flashing red light!! So that key fob has manual lock and press button unlock!!

It’s different, but I would like both buttons working, don’t know where to look for a solution.

Hello

https://www.rangerovers.net/threads/how-to-safely-have-a-p38-locked-with-battery-disconnected.179857/
From above site.
marty_nz 2015

“The way I disconnect the battery and secure the vehicle - and what I advise others to do on their P38s is to disconnect the battery with the vehicle UNLOCKED,

And then manually close the doors/lock them with the sill locking buttons, and then manually lock the drivers door with the key.”

YES I DID THAT it worked the vehicle was all locked.
A few days later came back used key in door to unlock and went on with the mechanical job. I had to lock and unlock several times with the key in door during the job.

Work finished ….. opened the door, and window, and kept them open while I opened the bonnet and reconnected the battery.

When I have done this in the past there was the sound of the doors locking.
Drivers door still open but no sound this time, car not locked.

Put key in ignition all okay, turned key and motor started so no problems there.

Tried to sync key fob as I have done in the past ….no flashing red light this time …. no sync.
Tried the spare key same no sync.
Their batteries were new 8 months ago and both have been operating perfectly.

I have been using the car for a week now using key in door to lock/unlock.
All doors lock/unlock using the key except the passenger door…. it hasn’t worked electrically since I purchased the car 12 months ago.
The starting and running of the motor is not a problem.
Reset the windows, mirrors can be moved and self dipping function disabled okay.
Suspension all working.

Has anybody got any ideas on how I can get the key fobs to sync so the lock/unlock buttons are operational?

Thanks in advance
Andrew

Thanks Pete.
I have put your comment on my "To do on Bimbo" list. At the moment I will just be driving her especially now it's going motor wise and just got a wheel alignment so she is handling much better.

Next up is work on the Defender camper.
Andrew

It has been some time since I posted here, but the out come of my work seems to have had a positive result.
Old age has some unwanted side effects that slows progress. However a large amount of time was wasted, caused by an idiot employed by a local transport company. Three parcels of parts from UK & Germany arrived for delivery on the same day. For some reason he left them along side a roadside mail box, such mail boxes are common in rural Australia, on a road that was not even on my road. Road name signs are clearly visible. Somebody obviously has found a use for the parts as they were never seen again !!
So claiming reimbursement, ordering the parts again and delivery to the correct address this time took weeks.

Replacement or cleaning of
• MAF sensor cleaned it was very dirty requiring a great deal of one tin of cleaner.
• Air Temperature sensor cleaned also dirty but not as bad as above.
• New air filter the one in it was old & not exactly clean.
• New Fuel Filter the old one, on back flushing had a great amount of slurry in it !!!
• New PCV valve old one was totally blocked and took a while to extract. I should have realized that there were more problems to come with carbon build up. See below.
• New plug lead set. 8 New plugs NGK BPR 5ES.
• New Fuel Temperature Sensor test showed it was not working at all.
• New Fuel Pump installed … but didn’t fix the lower than specs pressure reading.
• Compression test done (but on cold motor)
1 & 6 165psi, 2 & 5 160psi, 3 150psi, 4 140psi, 7 & 8 155psi

There was some lessening of petrol in oil problem, but the motor still had a problem when hot at above 2,000 rpm. It ran rough and required planting the accelerator down to seem to clear it, maybe excess fuel ?

It was suggested on the forum that the problem may come from injector(s) miss metering fuel and/or a faulty Fuel Pressure Regulator. Thank you to those who suggested this possible problem, I think they were right.

• 8 New multi point injectors fitted. Old ones difficult to remove, didn’t look good, O rings poor condition. They were probably new 280,000 km ago!!
• New Fuel Pressure Regulator fitted.
• New Engine Temperature Sensor fitted. Old one not reading as it should.
• New Engine Oil Pressure Sensor fitted, replacing what was probably the original one.
• 2 New lambda sensors fitted (02 sensors). One appeared not to be working.

New oil, 300 ml of Molybdenum Disulfide, 300ml of Lifter & Tappet Cleaner and new filter and the car taken on 100 km drive, the engine now seems to run as it should. At 100 kmh and all through the revs ranges engine now running smoothly. Oil level where it should be.

There is a bit of what I think is tappet/lifter noise on start up but it gets quieter as I wait for the motor to warm up. I will only do another 300 km and I will drop that oil out and put new oil and filter on the motor again.

Renewing tappet cover gaskets revealed massive amount of black baked on old oil. Car is not a daily runner so hours spent scraping, holding nozzle of vacuum cleaner close by. Sump removed and scraped / washed out. Cleaned the partly blocked oil pick up gauze, renewed O ring. Cause of the flickering oil pressure light?

I am absolutely amazed that the engine still ran at all. On inspecting the car obviously the clean oil on the dip stick was put in for my benefit.

Andrew Owner of Red Bimbo.