At 390 grams it's a wonder it worked at all but a regas was definitely needed so should sort out the problem. When it was working, what sort of temperature were you getting coming out of the vents? When working correctly you should be getting really cold air coming out. In the UK at an ambient of maybe 20 degrees, air at down to 3-4 degrees is the norm but the higher the ambient temperature the higher the output, so I would expect around 10 ish degrees. You would have been getting the book symbol on hot days when it tries to engage the compressor clutch but it doesn't engage (so doesn't draw sufficient current) almost certainly due to the lack of pressure meaning the pressure switch is open.

ECM does signal the HEVAC, it tells it that the engine is running and the engine temperature is normal so it will allow the AC to be engaged. HEVAC also signals the ECM to tell it when it engages the AC compressor so it knows to expect the revs to drop at idle and to raise them. On a hot day as soon as you start the car it will try to cool the interior as quickly as it can by bringing on the AC and interior fans but not necessarily the condenser fans. As Sloth also says, with a properly working viscous fan it doesn't need them (they don't do much at the best of times). As long as they come on when the ECM knows the engine is getting hot, that is all that really matters.

Did you drill and tap the holes for the rear disc dust shield brackets to a larger size? The original bolts usually shear off if you try to undo them and the bracket suffers from rust too. When I'm next in there (new rear pads will be due soon) I'll be dealing with at least one of those. I've got a rattle from the offside rear whenever I go over a bump as the dust shield is flapping about.

HIGH SETTING:
145mm rear setting
140mm front setting
STANDARD SETTING:
105mm rear setting
100mm front setting
LOW SETTING:
80mm rear setting
75mm front setting
ACCESS SETTING:
40mm rear setting
35 mm front setting

Make them out of 30mm diameter material, Delrin, Nylon even wood but if too fat they won't fit into the bumpstops and too thin they will fall out. Level floor isn't essential as you are setting the distance between the axle and the chassis just make sure it is sitting on the blocks and not any residual air left in the air spring.

My fault, I referred to Extended when I should have said High. Don't forget the tapped hole in the end of the Access blocks so you aren't trying to lever them out after you've set it.

Another little tip. Screwdriver needs to be a number 2 Pozidrive, NOT Philips head. Dipping the tip in some grinding paste will reduce the chances of it riding out and damaging the head too.

Agree entirely, they are very logical just different to what people expect and know, blend motors and a controller instead of bits of bent wire. Although in saying that, the same blend motors are used on a number of other cars (Peugeot 406 being one) but I suspect they get scrapped before they start to play up. Yes,the RHS temperature and distribution motors can be accessed through the hole where the instrument cluster lives although you will need a right angled screwdriver to get at one of the screws. The bracket that the instrument cluster attached to will try to dig chunks out of the back of your hand so I usually take that out too. Common failings are the feedback variable resistor wears out but it can sometimes be resurrected with a squirt of switch cleaner or the motor itself getting weak or not working at all. You can test the motor with a 9V battery but ensure you unplug the connection at the HEVAC or you will damage that. If you take the blend motor apart, note that two of the cogs have arrows on them which must be lined up when you put it back together.

Yes, difference in temperature from side to side is a blend motor problem. If the O rings are done properly, using genuine LR O rings, they will last for about 15 years at least. Heaving on the pipes where they come through the bulkhead can cause them to start leaking though. If someone has already been in there then it may have been to replace them before and they either didn't align the pipes properly or overtightened them and cracked the matrix. In your position I'd get in there to have a look at exactly where the leak is coming from. If from the bottom of the matrix housing them it is a matrix problem but if from the O rings I'd replace them first and see if the leak is cured. For around £4 for the rings and a couple of hours work (if you've never done it before, half that on a second attempt), it's worth a go.

It has been found that the heater matrix from an Audi will fit with a little modification of the heater box to make it fit. I assume this is what is being offered as an alternative? This has stubs so you can put hoses directly onto that and do away with the O ring connection and alloy pipes. Personally I'm not a great fan of it unless you are going to use silicone hoses and constant tension clips. If using ordinary coolant hose and Jubilee clips they will start to leak with age and you are back where you started. There's also the problem of trying to fit the temperature sensor onto a non-metallic pipe.

Is it the matrix or just the O rings? O rings are dead easy despite what some would have you believe, but matrix involves taking the dash out so the heater box can be moved.

Remove both centre console side panels (2 screws in each, if they are both still there), lever outwards at the back and slide down and back. Undo the 4 screws that hold the HEVAC in place, tilt it out at the top then pull. Black plug on the left side is the one to the blend motors.

The switch......

There's 3 blend motors, one for each side and one for air distribution so it sounds like you have one or more intermittent blend motor. Pulling the HEVAC out and giving the blend motor connector a dose of contact cleaner might work. When you first start the car the blend motors are driven from one end of their travel to the other to check for a feedback signal. If the HEVAC doesn't see that signal, it won't try to move that particular blend motor again, or at least not unless it passes the self test on the next start. With working blend motors but non-functioning AC, putting it on Lo will give you air at ambient temperature.

Yes, as Garvin says, the Grey/Black isn't the power supply, just a turn on signal for the amp which gets it's power from the door outstation. While doing away with the amps is an option, they incorporate a crossover so the signals to the bass speaker is split from the signals to the midrange and tweeter. So if doing away with them, then ideally you need to fit crossovers in their place.

First off it sounds as though you have the Mid line system and not the High line with amps in the doors and someone has fitted the HK tweeters with the logo on the covers (but not the HK bass and midrange units) and CD changer. Although Mid line didn't have the amps in the doors (mounted low down at the front of the door) and the head unit was wired directly to the speakers, but it also didn't have the CD changer, sub-woofer and steering wheel controls. My '96 HSE Ascot has the amps in the doors, CD changer in the boot, sub, steering wheel controls, HK logos on the tweeter housings and also on the door cards above the grille for the bass speaker. So you either have a Mid line spec that has had the extra bits added or a High line that has had the door amps removed (although I would have thought you would notice bodgery in the wiring to the speakers) or you simply haven't found them.

As someone else has already been in there you've no way of knowing what has been done to it so your best bet is going to be to go back to basics. Test from head unit to speaker by connecting a 9V battery across it and listening for the thump (or try connecting temporarily from head unit output to speaker). If you do have amps but haven't found them, they need power on the Grey/Black wire to turn them on.

Sloth wrote:

That said if you want to fly me out to you, I'll happily bring diagnostics and recovery/evac/recharge kit with me to diagnose and regas it once we find the problem. No charge, just cover my travel costs :P

It would be interesting to see what airport check in would make of a 10kg cylinder of R134a and an empty recovery cylinder too. I was once stopped from boarding a plane because I had a pair of gas shocks in my hand luggage. Then again I was also stopped once when my luggage tested positive for Semtex which turned out to be two dead Duracells in the remote for a satellite receiver I was taking over for a mate......

The '96 has been used mostly by my other half to carry building materials for a house we have been renovating. Tools in mine (the '98 ex-plod, now with 443,000 on the clock) and sheets of plasterboard, plywood, wall tiles, etc in that one. A lot more practical than her Merc SLK280 and quicker than two trips in mine.....

It depends what sort of a mechanic he is. Some are fully skilled parts swappers, the better ones will try to diagnose the problem first. However, with AC, virtually everyone will go for a regas first, providing that is done properly (recover, pressure test, vac out, refill with the correct amount of R134a). As far as sensors go that could be inhibiting it, you've got the aspirator (the cabin temperature sensor in the dash) but if that was to go open circuit it would detect a cabin temperature of -40 degrees C so wouldn't engage the AC compressor as it thinks it is cold already. You've got the heater core sensor which, again, if open circuit tells the HEVAC it is at -40 degrees C although I think that will only stop it from heating not cooling if the cabin sensor says it needs it. Then there is your suspect, the evaporator sensor which will shut it off if it is getting too cold and likely to freeze but it wouldn't prevent it engaging the compressor, it would engage, get very cold then disengage as the temperature gets low. But you need diagnostics to be able to see what the various sensors are reporting.

However, thinking it through, you've got an early car which drives the compressor clutch directly and not via a relay like the later Thor ones do. In the case of an early car, if it tries to engage the clutch and the pressure switch is open due to a lack of refrigerant, the HEVAC detects that it isn't drawing sufficient current so logs the fault, brings the book symbol on and doesn't try to engage it again until it is reset the next time you start the engine. So you would get a very brief flash of your LED the first time it tries to engage it then after that it won't try again. So the regas may just be all it needs.

When working correctly, one of the refrigerant lines should be too hot to touch while the other should be very cold and may even have condensation forming on it. If you can touch both then it isn't doing anything. However, even if low on refrigerant you would still get the signal from the HEVAC to engage the clutch, it just wouldn't get as far as the compressor due to the pressure switch. So it does sound as though something is stopping the HEVAC from engaging it. Ideally you need diagnostics that can show you what values the various other sensors are giving.

P1179 is listed as Maximum Negative AMFR Correction Fault which means the adaptive value for the MAF is as low as it will go so it has reached the maximum limit. Reset the adaptive values and then check the readings from the MAF. They should be 20 kg/hr plus or minus 3 kg/hr at idle speed and 61 kg/hr (again plus or minus 3 kg/hr) at 2,500 rpm. This is checked at sea level, engine fully warmed up, in Neutral and with all electrical loads off.

If they are outside of these specs, the ECU will add a correction factor to keep them in spec but it can only adjust by a certain amount and yours has adjusted beyond that.

Usual one for drivers airbag fault is the connector underneath the steering column, so dropping the knee panel is all you need to do to get to it.

One of my condenser fans seized years ago so they never ran and I recently noticed the other has now seized (probably due to lack of use) and it hasn't affected anything else.

One thing that will cause the compressor clutch to not kick in on hot days is if the clutch air gap is too wide. It should be between 16 and 30 thou but mine was nearer 40. It would work perfectly up to an ambient of around 22 degrees but as soon as it got hotter than that, just when it was needed, it wouldn't. Set the AC on Lo which should force it to come on, then tap the end of the clutch with a screwdriver handle, if it kicks in, that is the problem.

Yes it will. Doing an individual corner at a time shouldn't take too long with a tyre pump as you are only filling the air spring, probably a lot less volume than blowing up a tyre. Filling the whole system, all 4 air springs and the 9 litre reservoir, will take quite a bit longer (the best part of half an hour when I tried it with a fag lighter tyre pump).