agreed it is the wrong approach, although it's not actually 50W. 12V / 12ohms = 1A, therefore 12W. The 50W resistor is LR's way of making sure it will not burn out.

yes that's correct. You said you bypassed the relay (pins 30 & 5), after which the HEVAC engages the clutch properly ?? If yes, then it could be the relay is not pulling enough current. However if the compressor still only engages for a...

It does sound like early HEVAC behaviour, because when you bypass the relay it sees the higher clutch current draw ? Could also be a bad relay, so swap that for a new one first ?? Depending on ambient temperature, the compressor should be on...

also test the relays

If you look in RAVE it's all explained. HEVAC enables the fans, but unless pressure-switch-2 engages (247psi) they will be off. The exception on petrol is when the engine gets really hot, the fans will also be turned on. The...

I'm fairly sure one of my HEVAC is the early version, mainly because I had clutch gap issues causing intermittent operation. Both of them in my P38's and my spare all have heated seat buttons. Only real way to tell is to take the unit out &...

Before you go that route, take the HEVAC out & check the part number to verify if that could be the issue. The tech bulletin for early P38 & HEVAC is attached & shows the resistor. You already have the relay installed, so do what Keith said &...

Fans are a separate issue to the compressor only engaging once. - Pressure Switch 2 is to turn on the fans either if pressure >>247psi, but the engine ECU will override if engine temperature gets too high. - Dual Pressure switch only turns them...

+1 on this. Remember a prev owner may have swapped the controller due to LCD issues, etc. Simply the early HEVAC will engage the clutch once, but not see enough current, so it thinks to clutch is faulty & disengages again until the next time...

The diagrams are all in RAVE.

Also has the HEVAC control unit been replaced with an early version ?? If it has, then it needs an extra resistor so the output drive transistor thinks it's powering the clutch direct.

+1 on first job is to sort the LH Blend motor. Remeber the book symbol comes on for any faults within the HEVAC system. Probably worth getting a set of AC gauges & check the pressures. Even if you never re-gas yourself, at least you then...

There are no code for the dual-pressure switch. If the pressure is above 35psi it will be closed, so the HEVAC can engage the compressor. If the gas stays between 17psi & 305psi then it will remain closed & allow the HEVAC to control the...

I have a couple that definitely have issues with solder joints on the wires into the PCB, although that could be PCB track issues. Was planning to replace the capacitor at same time. Will try your heat trick (but not too much heat) !!

I was digging this one for many days in spare time. Still cannot get the PCB out. Is there a trick ?

Has the car got the clutch relay, or the earlier version driven directly from the HEVAC ? If it's the early version, check what voltage the clutch is actually getting. I had a problem on my 1998 where the clutch was getting intermittent...

+1 on this. There must be some heating effect in the clutch coil, so if the gap is too large it migh not pull in properly after the first time ? Gap should be 0.4 to 0.8mm.

Have you check the belt is not slipping (simple things 1st) or AC clutch ?

Not many smoothing capacitors on there ? Any interferrence issues ?

Marty experimented with his own driver pack, but apparently had issues with glitches due to interference. Work & family stuff got in the way of further development. If it wasn't for that damn potting compound, the existing packs would be easy...

How much ?? I have a couple of driver packs that have intermittent wires, but cannot access the PCB to resolder them. Tried digging out the compound but still cannot get the PCB out.

Might help to know which engine it has ?? or did I miss that ??

GEMS has a setting for 4.0 or 4.6, but cannot find anything in the Nanocom for Thor ?? Either the original Thor ECU might learn the new engine behaviour, or it will under/over fuel because the firmware is wrong !! Best talk to one of those ECU...

what vehicle is that from ?

I have seen similar. If the blend flap happens to be close enough (and the HEVAC does not do calibration on that drive), then my book symbol sometimes stays off. If I then adjust temperature, the stuck motor brings up the book. Most likely...

Hi yall. Coming back here to conclude this thread. We fixed my EAS problem. The main problem was beep beep, "EAS fault" and car immediately either jumping to wade height or sometimes dropping to bumpstops. The fault would always come when the car...

Brian, are you back home yet ?

Did you top up with the engine./gearbox cold & engine idling? I assume no MAF on your car?

beat me too it Keith !! Was typing as you posted.

Test result was vague. Told doc I had ear infection again, hence penicillin, but it sorted the dull ears & taste issue. Maybe it was false positive !!