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1995-2002 Range Rover P38A
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If it is too large, hold the clutch outer and remove the central nut. The clutch outer is on splines and simply pulls off and there are shims behind it. Remove shims until the gap is correct.
Mr/ Ms Guest is almost right!
It's the inner that you need to hold (the bit that the belt doesn't run round and spins when you turn it with your fingers), three nice handy holes for a pin spanner or alternative in it for that purpose. Then remove it, then adjust shim to suit.
 

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Mr/ Ms Guest is almost right!
It's the inner that you need to hold (the bit that the belt doesn't run round and spins when you turn it with your fingers), three nice handy holes for a pin spanner or alternative in it for that purpose. Then remove it, then adjust shim to suit.
Thanks guys

I just got it regaled the other day so if its leaking it is leaking fast. When it working as it should its super cold so i doubt the gas is low already.

Yeah I already read about the air gap and the shims. I thought it was only one shim in there that needed to be removed, maybe there are more? If so do I take em all away? Also do the belt need to come off, I think Ive seen threads about this before.

Erik
 

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Belt doesn't need to come off as the bit you are removing is the bit that is connected to the compressor, not the pulley. Some have just one shim, others have more than one. Mine had just the one and taking it out gave me a gap exactly at the minimum value. Another I did for someone else had two in there and only one had to be removed. If you've only got one and taking it out makes the gap too small, then either find a thin washer or grind the existing one down.
 

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I ran down to the truck and got the clutch plate off by jump wire the compression and undo the nut. I had one shim in there and it seems like everything works as it should. I engaged it on and of a couple of times with the jump to the battery and made sure it spinned freely before I started the car up.

Hopefully it cures the problem that the ac stops when I need it the most.

I'll probably get a updated hevac unit as well

Thanks a lot

Erik
 

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1995-2002 Range Rover P38A
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I have tracked down a JFC102550 Hevac unit locayl and I will check it out to see the condition.
But now a new AC related thingy have shown up. When car starts up and it shows 0 degrees no AC, driving for a while and temp rises the clutch kicks in and it works fine. Though when outside temp reaches above 20 degrees it stops again and only blows warm air. The 0 degree thing I can live with because when it reaches 4 the AC actually kicks in but above 20 is a big problem.

When I drove home tonight it was steady 18 degrees outside and climate control inside the car was perfect. During the day it was about 24 and the inside was horror.

Now to the question that Marty might have an answer to?
Would the
JFC102550 Hevac unit also cure this issue or is this something else?

Thanks
/Erik

Current issue was covered by the following LR Tech Bulletin:
hevac.jpg

Concerning the research I`ve recently made, the problem occurs due to faulty eeprom. The eeprom is used by board processor to store/retrieve operating data. I`ve desoldered board eeprom to read/write its data.
hevac-board.jpg

After number of read/write cycles I`ve defined that the eeprom failed to write data on several cycles. The next step was to test it in heated action. During heating it up I`ve noticed that the retrieved data has changed (offset binary) right @ ambient temp address. After "chilling out" the data returned to initial readings. I`ve soldered in a new eeprom and the issue has gone but still keep an eye on it for any update. Regards,
 

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1995-2002 Range Rover P38A
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I'm not going another winter without heated seats, so I bought a HEVAC from Europe with heated seat buttons and a heated screen (although that's not fitted to the car).

My car's a 2000. This HEVAC unit was made in 1994 - it must have come from one of the earliest P38s.

I removed relay three in the fuse box and fitted the jumper. Fitted the HEVAC unit and with the engine running, the BECM clicks on and off with the heated seat buttons (haven't tested yet if the seats are actually heating) so all the controls are working.

The issue is with the new HEVAC unit fitted, I get the testbook symbol. Should I assume that this unit is faulty, or have I missed something obvious?

I've read everything I could find on fitting a pre-Bosch HEVAC to a Bosch car and it seems that the jumper pictured at the top of this thread and at Stockholm Views is all I need to do.

Any help much appreciated.

Tom
 

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If I can't get that HEVAC working, I think I can do it by putting switches in line with the two wires to C255 to the BECM.

These two wires are active low, according to the wiring diagram, so cutting the power should cause the relays inside the BECM to click on and power the seat heaters.

Correct?
 

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You could try this mod if you are handy at soldering SMD components... (It worked for me)

I had the same issue after getting a replacement 1995 module (JFC101890) for my 2001 AU P38 to fix the faulty LCD display. My vehicle originally had the HEVAC module JFC102540 which does not have the heated seat buttons, so recently I thought it would be nice to also add them. I did not know the differences between the two at the time I bought the module (years ago) and I only wanted the working display at that point.

The Original board in the 2001 P38 contained a BTS432I2 Smart Highside Power Switch FET to control the relay, while the older board has a BTS432D2 (higher current version) to drive the compressor directly. There are slight differences in the status output pin (ST) and current rating on these devices which I think leads to the FET outputting a fault code (ST pin low) which shuts down the compressor, as it doesn't sense the correct load when only driving the relay in post '98/99 models.

Datasheets for the two FET's are here: BTS432I2, BTS432D2

Instead of changing these components over, or adding 40W of load (power restistor) to simulate the compressor on the output, I went the route of just removing the connection from the output status pin of the FET (pin 4) and connecting it to Vcc (5V)..This tricks the HEVAC module into thinking the FET/compressor is functioning normally and the error goes away.

This was made super simple as there is a 100k SMD resistor coming off the status pin of the FET which happens to be right next to a Vcc (5v) pad. Just unsolder the SMD resistor, turn it 90 degrees and resolder it across Vcc instead of the output of the FET. No need to even cut tracks!

To remove the PCB from the HEVAC module, you only need to remove the aluminium plate (6 torx screws) and unclip the ribbon cable to the display/control board. You could probably do the mod without completely removing the board as well, but I found it easier just to remove it..

Schematic of mod (changes in red):

286480



Board component side showing location of BTS432 FET:

286482



PCB before mod (from original board):

286486



PCB with mod completed - This shows the location of the resistor relative to the BTS432:

286483



Hope this helps.

Cheers
JC
 

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1995-2002 Range Rover P38A
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Nice work!

I've often wondered if there was a simple mod that will allow this - but have never actually had time to sit down and trace out that status pin to see about bypassing it.

Might be something I look at doing on some of the older units I refurbish... as that fault showing up is somewhat annoying!

Thanks for the helpful post and the pictures!!

Marty
 

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Brilliant mod - and brilliant first post, Sea Captain!

It's obviously much better to have the HEVAC drive a relay, rather than have 4A in the HEVAC wiring. The compressor clutch measures about 3 Ohms. Did you fit the two heated screen relays or 80 Ohm 3 Watt resistors across the missing relay's coils?

I recently fitted a 1994 HEVAC to my 2000 for the heated seat function and got it all working, but the original HEVAC is better.

It more quickly got to the desired temperature and seemed to be better at selecting the 'right' cabin temp.

When I fitted the 1994 HEVAC front panel on to the 2000 HEVAC control PCB, it would not operate the heated seat function.

I suppose I could source another 2000 HEVAC (expensive purchase as they have to come from the USA or UK - Aust cars never had heated seat controllers) but does anyone know how to mate an old front panel to a new control board?

Thanks

Tom
 

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2002-2005 Range Rover MkIII / L322
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I initially fitted the upgrade kit and removed a shim (way back when...) but it didn't fully solve the problem.

So I machined a little off the clutch boss to reduce the air gap. That worked - and worked for many years at least up to when I sold the P38A in 2015. It was written up in the old RangeRovers.net tech pages.

Clutch before machining:

286502


Ready for machining in my lathe:

286503


After machining:

286504
 

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Thanks!

I just added the relays for the heated screen as I had a few lying about.

Unfortunately my heated seats don't work yet. I get power to the connectors under the seat when operating, the elements in both seat bases have failed, the back ones have continuity at least. Yet another task on my long list of things to do.

I was just amazed they built the seats with the heaters in them in the first place, and went to the trouble to remove 2 lousy buttons on the HEVAC panel in Australia so we can't use them!

As to just swapping the display part of the module, I tried that as well initially, but had the same result, the heated seat buttons would not operate the relays. I assumed this was due to the output control being done in the control board's processor. I didn't look any further into tracing that part out (yet).

It would be interesting to know if the older display board is compatible, might be able to find a JFC102550 module cheap with a faulty display and just swap the control board?

There is a micro-controller/LCD driver on the display board, so it would depend on whether the heated seat output is controlled from there or the control board. I do know on the JFC102540 display boards, the LED's are missing for the heated seat/windscreen buttons so the blanking buttons were not the only difference.

If I can find a cheap one, I'll give it a go and report back.

JC
 

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2002-2005 Range Rover MkIII / L322
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I was just amazed they built the seats with the heaters in them in the first place, and went to the trouble to remove 2 lousy buttons on the HEVAC panel in Australia so we can't use them!
I once asked an engineer (a real engineer, not a serviceman that the Pommies call engineers) I know and who worked at Solihull. He said for the P38A, Australia wasn't considered a cold place so it didn't get the cold climate option.

It was probably easier and cheaper to set all seats up with heaters. (My wife likes hers in our L322 - mine doesn't work.)
 

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Yes of course. From the people who set the great southern land up as a penal colony then put their prison in the most inhospitable, frozen part of the land - that's Port Arthur in Tasmania.

What? it gets cold in Australia? surely not, old chap. It's all desert sand and spiky reptiles down there. Heated seats? Let those blighters freeze, and put another willow log on the fire, chum. That's the engineering team in Building 38A planning the replacement for the RR Classic.

I love my seat heater. I'm going to add a less hot setting with a power resistor. I think a few cents worth of copper meant it was less expensive to build them all with the elements fitted.

Tom
 

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I was once talking to the owner of the first Hyundai dealership in the UK who told me about a meeting he had with other potential dealership owners and Hyundai when they were first setting up a dealer chain in the UK. At the time if you wanted AC you had to buy a Roll Royce, a Bentley or a Jag as nothing else on the market came with it but Hyundai proudly told them that all their cars came with air conditioning as standard. His view was that it could be a good marketing point, a budget car with a luxury feature. The other dealers didn't agree saying that nobody needed air con in the UK so it wasn't necessary. So the RHD cars for the UK were built on the same production line as those for the Japanese (and presumably Australian) market but were then taken to one side to have the AC removed.

I suspect much the same happened with the seat heaters on the P38. Some misguided person at Land Rover Australia, no doubt based in a warmer part of Oz, told them that heated seats wouldn't be needed so you didn't get them.
 

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Yes, Jaguar Land Rover at the time had their HO in Sydney which gets bloody hot in summer (48.9 deg C/120 deg F last January where I live in Sydney's west) but doesn't get very cold in winter. Not cold enough for me to wear long pants and long-sleeved shirts.

 
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