I haven't found a replacement, no - but I have sucessfully de-soldered them and opened the switch up and cleaned the contacts internally and got them working again.

However, if all of them don't work, then check the PCB in the overhead light unit - I've seen it before where they've had moisture drip down (possibly just from condensation even off the metal roof) and over time corroded one or more of the tracks away on the board. I've repaired a few by bypassing the affected area by soldering a new jumper wire on.

Marty

I thought your one had been upgraded to a new RF Receiver?

I have some RF Filters available again - so drop me a message if you want one at any point!

Marty

Yes, The screens are all the same... it's just the actual plastic face panel, buttons, and firmware that are different between the HEVAC models - but the LCD screen is identical

The Zebra strip is basically a sandwich of very thin materials - they're layered with a conductive strip/insulating strip/conductive strip etc all the way along them - so the current flows though, but is isolated every other layer, so that between the copper contacts on the PCB and the contacts on the screen, they always have conductive strips, and isolating ones, so one set won't short to the next one etc.

Re not getting all the pixels.... cleaning the zebra strip could help, as if there's some dirt or old adhesive on it from where they stuck it down, then it could be insulating where it should be conducting. The other thing to check is the screw holes/mounts that hold the PCB to the plastic fascia. There's only 2 of them on the bottom of the screen, and I've seen a number of times where they have cracked, so that when you tighten the screw up, it doesn't give enough grip and thus not enough pressure between the screen and the PCB, and you can still miss pixels. If that is the issue, I've sometimes repaired them by re-melting the plastic with a soldering iron where it's cracked - but you have to be careful to not do any more damage.

I've got a handful of HEVAC screens which have a fault in them where one or 2 pixels still don't work, and they are actually a fault in the screen somewhere - but if you got all the pixels before, then I'd say the chances aren't high of the screen having failed now - unless something got scratched/damaged when you removed the old residue from the original ribbon strip.

If you can post up a picture of the back of the HEVAC face plate, then I might be able to tell if the screw mounts are an issue or not.

Marty

No worries! Hope all is well with your respective P38s still!

Back in NZ now and busy with work again, and preparing to battle with customs to get my stuff here without having to pay stops amounts of tax because according to the removals firm, my travel movements over COVID make me ineligible for duty free import of my personal possessions... And have noticed useless for any kind of help (despite paying them nearly 4k to move my stuff!).... No advice or compassion either just "it's your responsibility to know the regulations"... Again despite them shifting things around the world every day for people and me never having shipped stuff off this magnitude to the other side of the world before... Rant over haha

I'll try to check in on here on some of my days off 😀

Cheers,
Marty

If I was a betting man, I would say it will be the RHF latch that doesn't lock/unlock with the rest, and therefore is the one causing the problems.

It seems to be the most common one, and my theory is that because the tailgate motor grounds through the CDL switch in the RHF door. The switch contacts are only rated at 0.1A, which is fine for logic signals, but I feel it's a bit low for the motor ground. Which is one of the reasons the RHF CDL switch in all my refurb latches is beefed up to 5A (not that the motor will draw anything like that - but gives some headroom, and it was a standard rating I could find).

Chasman wrote:

Take 2:

I bought this tone generator: allsun Automotive Short Circuit Tester Finder Cable Tester Wire Tracker Detector Tone Generator EM415PRO https://amzn.eu/d/bTFyJJz

All trim and kick-plates are off but carpet is still down on passenger side. Traces all the way from the load area to the female plug under the driver's seat IF it's UNPLUGGED.

EDITED:

Tone can be detected all the way from the load area to the door on both wires... I assumed all the soaking in Contact Cleaner and cycling if the plug had fixed it.

I vote the car front to back not left to right like JLR So FR is Front Right and FL is Front Left. The crossovers say woofer so I use W in the codes but call the speakers bass.

To eliminate the FR crossover I connected the FLW wires to the currently vacant FRW terminals: Sound from FL bass driver.

To eliminate the FR bass speaker (again) I connected it into the FL door: Sound from FL bass driver.

Left FR bass in FL door because there's no point switching it back when I know both of them work.

Switched FL bass wires back to FL crossover. Tested and still working.

So, I now have GR/BL and BL/GR wires for FR which pass the test tone all the way from the load area to the door and a known working speaker from the FL door.

Fitted and connected FL bass to FR door, reconnected GR/BL and BL/GR wires to the (now) known good FR crossover.

Silence. Nothing. Nada. Null point.

That is an odd one...

Have you tried the continuity test with your multimeter from the loadspace to the connector?

The only other thing I can think of (without it being in front of me to poke and prod at myself) is that when it plugs in there's a high resistance, which stops the tone. Out of interest, have you tried reading from the loadspace connector to the door connector with resistance (on ohms on the multimeter, rather than continuity check). The continuity checker on my multimeter goes up to maybe 200? ohms resistance - so anything over that, if there IS a connection, but it's high resistance, then it won't read anything - but if you click it to say the 2K ohm range, you don't get the continuity beep, but you can see if there's a resistance along the wire.

Might be something else to look into, in case there is a problem in that connector...

The ONLY issue I found when I had my (albeit Thor) LPG in series with the heater, is that sometimes in winter, it would take forever to get heat in the cabin, as most of it seemed to be sucked out by the vap when I was running on LPG.

I don't know if part of that was the size of the vap on mine, or the Audi heater core I had at the time had slightly smaller hose inlets, or the flow through it just wasn't enough to warm the heater core enough for me to get hot air inside - but since I swapped it back to being in parallel, I get warmth from the heater again, and I've had no issues with the LPG vap freezing up. Mine does also seem to have (what I would have thought) a smaller vap on it, so it could also have been restricting flow through the circuit to the heater.

After my heater core exploded when the PS pump failed and the serpentine belt got shredded, I replaced the old Audi core with one of the Nissens ones with the 19mm hose outlets, and it definitely has a lot more heat than the old one with 16mm hose.

Thanks everyone for the patience whilst I've been away so much, and not had time to do anything P38 related - including answering emails/being on forums...

The movers are here currently packing a load of my stuff into a van, and I'm flying back to NZ on Wednesday afternoon... Nick has the rest of the filters here, so any that sell can be shipped from the UK.

As Richard mentioned - a couple of the parts have been impossible to find the last couple of years - the main microprocessor being the main one of them... They do seem to be available again now, which is good - but the ones I made whilst I've been here have used up our stocks of the PCB, so I am in the process of redesigning the PCB to all be with surface mount components, which I can get assembled at the PCB manufacturer, and hopefully a) make the filters quicker/easier to produce and b) mean that I can get more of them in batches, but then it means that I don't have to spend hours researching components/finding which supplier has 'x', who has 'y' etc - and I can just focus on programming the board, and then making the wiring loom/fitting it all to the case.

It might mean that some of them will ship from NZ (which might be better for Australasian/US etc orders)... but I will also look into sending a batch of assembled units to the UK for distribution locally.

I'm also looking at making microswitch 'blocks' to replace the ones in the latch - so again it could be possible to DIY replace the switches, rather than having to buy a whole refurb latch. Though I have shipped I think 8 LH and 8 RH latches to NZ so I can finish rebuilding them and hopefully have them available again in the future (for people who don't want to pull gross horrible latches apart, or want to have to solder wiring). But it will be a few months before I can work much on these as the shipping time is due to be 8-12 weeks before I see any of it again.

Hopefully I will be able to have/find/make some time in the future again to get back on the forums and be a bit more active... will have to see how work goes!
I might even sneak in a topic somewhere on some L322 projects on my one in NZ... there's lots I want to play with on that, but haven't yet had time to even look at!

Cheers,
Marty

Chasman wrote:

Progress of sorts. Found the connector under the driver's seat, Thank you!

The wiring through the elbow sheath in the door to the male plug is intact. I tested one of the suspect wires in the female plug to the load area and it's broken.

1 is there a second plug over the passenger side? i.e. is the production line split left and right with one station putting in bridge components across the middle?

2 is it worth buying a tone generator and probe for £25?

Well, that is some progress then!

Unfortunately, there is no other connector between there and the loadspace - it is a single wire from there all the way to the DSP amp. The loom runs across the back of the centre console, under the passenger seat behind the ECU's there, and then down into the sill under the plastic covers, and then along and up past the rear seats, into the loadspace.

Tone generator - might be useful - but the wires will be bundled together with a load of others in the loom - so I don't know what kind of interference it might introduce. I would pop the sill trim off on the L/H/R and have a look at the cables in the loom there and see if there's anything obvious. You should also be able to get the trim off that goes up the side from the floor to expose the wiring there too, which might allow you to check a bit more without having to take the loadspace trims off and the rear seatbelt mounting bolt out to get that last trim off...

It feel like you are definitely on the right track!

Marty

That is odd on those wires. Hopefully something will show up with that connector. Also worth checking in the wiring loom in the sill under the plastic cover at drivers door. I've seen breaks in the wiring loom there before. But definitely worth checking out that connector. At least it gives you another point to test from/to which will narrow it down.

Tailgate wire... Yes, it comes from.the CDL microswitch in the latch. It supplies a ground path for the tailgate motor (through the button in the tailgate too) when the drivers door is unlocked.

That way when the doors are locked, the tailgate switch has no ground, and thus the tailgate won't open and is locked with the rest of the car.

Philip wrote:

Thanks Marty, very useful - interested if you do have any latches.

I had a look today as I was sorting through a bunch of my P38 stuff... I have a drivers door latch with the moulded connectors already assembled and available. I don't have a passenger one assembled, but I have one here which I will try to strip/rebuild tomorrow so it's also available.

Fingers crossed my P38 passes the MOT tomorrow, so I can get out and about rather than being at home a relying on deliveries... and I can get some epoxy to finish the RF Filters aswell...

Cheers,
Marty

Morat wrote:

Gonna miss you in the UK mate!

I'll miss being here (at times!) I definitely will be back again for visits (especially until I decide to sell the house). I'm hoping that I'll end up having a bit more spare time to be able to actually get back on the forums - and potentially work on some more parts - even if the shipping is a bit more expensive from NZ. I have a few more ideas on P38 projects that I want to do, including a 'drop in' replacement switch pack for P38 door latches... I've prototyped a few up whilst I'm here (using some 3D printed parts) and going to include a bunch of door latch parts in my boxes of stuff to go to NZ, so I can potentially do some rebuilds of them, and test out my new switch blocks.

I'm also going to have my P38 BECM tester and diagnostics with me over there, so hopefully some BECM services will be back on board again too - shipping a logic board isn't the end of the world, so fingers crossed the distance doesn't prove too much...

My partner has never been to the UK, and I'm hoping she can come over with me next year (as I'll have to come back to sort the workshop out/potentially shipping the P38 to NZ) - so hopefully there will be some time for showing her around the country - so will have to come up your way to catch up!

How's the Duchess going?

Yeah, the wiring in the later ones is a mess with colour codes - it's almost a case of "what do we have left... oh use that now"...

I think the wiring diagram/list that I put together was from RAVE and what was listen in there, but I think I also saw in mine when I took the door card off that the wires in the RHF door loom were the same as the LHF, and weren't what matched RAVE after all.... not the most helpful!

Interesting that the Green/Black and Black/Green are both faulty.... I could have expected one, but not the other.... you definitely have continuity on both of them from the speaker connector through into the vehicle somewhere? They are the wires for the Bass speaker in the door, and are (from memory) thicker wires than the mid/hi.

I have just looked back at the pictures I took when I had all my interior out of the P38 after I bought it (as it was manky and I re-carpeted it, so literally pulled the entire interior out). The connector which I believe is the one you are looking for is right behind the BECM in the rear passenger footwell (drivers side) - it's a big grey connector. The loom then carries on across behind the centre console (under the carpet) and then under the back of the passenger seat, and into the sill back to the LHR wing area where the DSP amp resides.

This pic is from when I had the interior of my P38 out, and I've circled what I think is the connector that the stereo wiring goes through...

Hope this helps,
Marty

I will have a look tomorrow and see if I have latches to suit the '95s. I am pretty sure I have a drivers side one, and if I don't have a passenger side one, then I'm pretty sure I'll have the bits to make one.

I also should have RF filters available again later this week as I have been able to finally source some of the microcontrollers which have been unobtainable for the last couple of years...

I'll drop you a message on here or PM me your email address and I will email you once I've looked through my parts here. (It's a bit of a jumble as I'm still sorting what I'm going to take overseas and what will stay here! But should get time tomorrow to have a proper look for you)

Cheers,
Marty

The later vehicles at least had a connector with a load of the speaker wires going through it buried under the carpet behind the centre console (in the rear foot well). I found it when I had the whole interior of my p38 out years ago.

However, it seemed to be pretty secure and not likely to be able to get water in it, so don't think that will be your problem.

The next place I would check would be the wiring from the door into the vehicle. If you pull the rubber cable sheath off from the bodywork side, you can just get the connectors out of the bodywork. The speaker cables run through one of the 3? Connectors stuffed into the A pillar, and they are also known for getting green and horrible. You can probe for continuity there aswell, to be able to tell if your is there, or in the door wiring, or on the vehicle wiring.

The only difference to the later HEVAC with regard to temp sensor is that it will hold the last value of the external temp until it's detected road speed for more than 10s.

This was added when they moved the sensor to ensure there was fresh air without latent heat from the radiator etc (because of where the sensor ended up being mounted) before the HEVAC used the reading. If you've had the HEVAC disconnected and powered on, or the sensor disconnected etc then you sometimes will see -40 on the external temp until it's had a chance to update. Other than that, the sensors are the same and the only other main update to the HEVAC was the compressor clutch fault being changed, so it wouldn't trigger with the wiring update where it drove a relay to power the compressor clutch, rather than direct from the HEVAC itself (which wasn't powerful enough - especially as the clutch gets older/wears/requires more current to activate).

Gilbertd wrote:

Bloody hell, you're alive!!!! I've been asked by a number of people if you were still about and I've had to tell them that you (and Nick) had gone AWOL. Welcome back mate, are you in the UK or did you just manage to find a bit of spare time to pop up on here?

Yes, I am alive - just been keeping stupidly busy over the last 18 months, and pretty much had no time for anything RR based - not even on my own ones where there are plenty of projects that I want to work on!

Currently back in the UK, yes - but only for a couple more weeks as I'm sorting through my stuff and packing it to ship to NZ. I am hoping that once all of my stuff arrives there, I can get back into some P38 projects. Though I managed to catch up with Nick the other day (He's been stupidly busy too, and I haven't really been in touch with him much in the past year or so either) and we are hoping to be able to get some things looked at (like some more RF filters made now I've actually been able to source some parts) whilst I'm here. Though going forward I might look at doing a re-design of the RF filter, so we don't need to do as much assembly on it, to make it easier for me to be able to look after making them in NZ and shipping them from there, either directly, or to Nick/someone in UK who can then distribute them. Things like that will need a bit more thought once I've managed to get my stuff safely packed up and shipped overseas though.

In the meantime, I will attempt to jump on here a bit around my packing/sorting etc

If you've got an earlier 1995, then these had issues (which later BECM firmwares fixed) with spurious RF causing the BECM to freak out and constantly lock the doors.

Later BECM firmwares obviously has something written into them, so that if it got an overload of RF then it would only relock the doors a couple of times I think, before it would then not try to drive the motors again.

I saw it a LOT on earlier vehicles where the front door latches would burn the motors out, but for whatever reason (maybe because they were driven by the BECM directly, not the outstation like the front doors) the rear ones never suffered this fate.

The bad news for you is that you need 2 new front door latches to fix it. From what you have described, all the latch microswitches are working as they should - the key is unlocking/locking the vehicle and setting/turning off the alarm/immobiliser. The drivers loor lock will always lock/unlock with the key in the door as it's mechanical. The microswitch is obviously triggering as the BECM sees the change in state and locks/unlocks the rear doors, but the passenger door doesn't do anything as the motor is burnt out. Likewise, when you lock/unlock the passenger door with the button in the door card, it is mechanically locking/unlocking that door, and triggering the central locking switch. The BECM sees this and signals to lock/unlock the other doors - but since the drivers door motor is burnt out, it won't do anything.

The best overall fix for you would be replacing the 2 front door latches, and an upgraded RF receiver (I'd say one of our fob filters as they're cheaper, but we don't have any at the moment - maybe in a few weeks if we can actually order some parts that have been unobtainable the last couple of years!).

Just be aware, that if you replace the front door locks, and not the receiver, then it's entirely possible if the BECM gets flooded with RF, then it could trigger the doors to lock and this will then cause the motors to burn out again. I've seen it before when someone replaced both latches, only to have them cooked again in a couple of months. With the updated receiver/RF filter this filters out EVERYTHING other than a P38 key fob, so the BECM is kept blissfully unaware of any other RF, and thus will only drive the door lock motors when it has received a valid lock/unlock code (or the key is turned in the drivers door or one of the front locking buttons is pressed.

As Gilbert says, some of the earlier MG latches work in a P38 - though some have an extra wire as I think they supplied a signal when the latch was locked aswell as when it was unlocked - from what I can remember anyway.

I think I have a RHD/RHF (drivers) latch in the early style (with the connectors moulded into the latch body) here which I refurbished aged ago for someone. I can't remember if I have passenger side too.... The later (version 2) latches would also work in your vehicle as the main 6 way connector is the same - but you would need to cut/ connect the black ground wire as the connector for that is different from V1 to V2 of the latch. The later V3 latches (whilst physically/mechanically the same) have a single connector on them, which is only compatible with the post '99 vehicles.

Hope this helps.
Marty

Bolt wrote:

I was just getting a few old fobs I have accumulated over the years ready to send off to have their codes read.
The plan being to input a known fob code into the HSK's Becm and see if I can get a working fob for it.....
Going through the fob bin, I found I had an extra fob for Bolt making 3......The one in the bin said it was key 1.
This got me thinking I could test my theory before sending a parcel to the UK......
I have read somewhere that you can only change the first code number (not correct) so, I went into Bolt's (unlocked) Becm and read the 3 stored codes. The first one happened to be 64, so I went to the HSK to input that into it's (also Unlocked) Becm. I found that the first number in the HSKs Becm was already 64......Caused me to recall I had tried this about 2 years ago without success.....
However, being a bit tenacious about this sort of thing, and seeing as I had no working fob for the HSK, I went ahead and loaded all 3 codes from Bolt into the HSK....What could possibly go wrong??
In this case, nothing went wrong, and the Becm accepted all 3 codes. Figuring one had to be correct, I tried to sync the fob.....
It WORKED!!.
I pulled the key from the non working fob that came with the HSK and inserted it into the now working fob.
As this is the Missus' daily driver, I am now a hero in her books!
I am going to send the other 2 fobs off to be read as they work, but I have no way of getting the codes for them.

This means, of course that if you have a fob on the correct band, a Nano or equivalent, an unlocked Becm, and a way to get the fob code, you can very easily make any fob work! Even the ones that they sell on sleezebay!!
Now for a large celebratory Rum!
Cheers!

Just a little bit of info for you on how this actually works....
You cannot input 3 fob codes into the BECM. The FOB code section is actually 3 bytes of data, as a hardware ID transmitted by the fob to the vehicle. The fob code you program into a BECM is the 3-byte ID of Key #1 of a lockset. The BECM then will accept this code and the following 3 ID's. This is how they get a 'lockset' of 4 fobs, and how they can program a new one from the factory, as there will be a record of the lockset barcode (which must have the ID 1 encoded in it somehow) and then say you want key 2 - then you can know what the lockset ID1 is, and then work out from that what the ID of 2/3/4 should be and program a fob to that ID, so that it would sync to the BECM.

The fob reader that I have will read the ID that the specific key is transmitting, and work out whether it's a Key 1/2/3/4 and tell me that. I can then work out (in the case that it's not a key 1) what the key 1 code would be, and this is what would get programmed into the BECM.

So if you have programmed your other BECM with the same codes, then they will both listen to the same fob codes (so you could in theory sync fob 1 to one vehicle and fob 3 to the other vehicle. but if you someone synced the remote from one vehicle to the other, it would operate it (on the fob at least) which could put the rolling code out on the other vehicle and de-sync it from there.

If you have other working fobs, then I would still probably get one of them read (especially if you have 2 from another vehicle/lockset) as then you could write the fob 1 code from the other lockset to the other vehicle and then have 2 working fobs for both vehicles... or at least 1 for one vehicle and 2 for the other. Or if you have multiple fobs, then read all of them, so if you need to replace one at some point then you have the codes needed for the rest.

In theory, I could get any key from any vehicle, read the fob code, work out what the #1 code from the lockset is and program it to any BECM - BUT you CANNOT take 2 keys from DIFFERENT locksets and get them programmed and have the BOTH work on the SAME BECM. you could program the fob code from one OR the other lockset, not both.

Regarding unlocked BECMs... I have read that there CAN be issues with unlocked BECMs, but I haven't been able to find out what they are either. The only thing I have read for sure is that you could get problems with communicating with the HEVAC if the BECM is unlocked. And that the fix for it is to unplug the connector to the BECM that has the diagnostic wires in it. I haven't however had the issues myself (my BECM is unlocked, and never have trouble talking to the HEVAC - not any worse than any other P38).... so I'm wondering if it was an issue on earlier ones that got fixed in later revision BECMs/firmware versions.

Marty