P38 02 Thor Brake & EAS

Mornin all. Just done brakes EAS & HEVAC.ATS did AC recharge. Held pressure, recharged but compressor wouldn't fire up. I suspect S/H control unit. Any other potential trouble spots? Suspension held up perfectly all through dash out, brake replumbing. Now drives N/S low. Both corners. TC lamp comes on but goes out on startup. ABS lamp comes on but doesn't go out until rolling. Seems like they're mixed up. Went to do Hawkeye ABS bleed but told it doesn't cover my vehicle. Only changed rear pipes and have a good hard pedal. Hope you can come with the cavalry. Best regards Peter.

There was a problem on earlier compressors where not enough voltage was delivered to the clutch to pull it in and start the compressor. You can tap the front of the compressor with a screwdriver to see if you can help it engage. I think though, they fixed it for the Thor engined cars, but might be worth checking.
Is there a chance you moved the suspension height sensors past their normal range of movement whilst changing the brake pipes? If you have maybe you've got rust or dirt on the sensor's track. A clean might help.
The ABS lamp should only go our once you're rolling, so that's working as it should.
All I can offer is that you re-bleed the brakes following the procedure in RAVE to the letter. It's bit of a faff, but the only way to be sure all is working as it should.

Don't need Hawkeye for bleeding the brakes, just the ignition key. As above, follow RAVE to the letter.

AC. Second hand control unit? Had issues here before. There are different models and I'm sure I heard a tale on here somewhere of someone who had one off eBay and it was a bit of a bastardised unit that someone had tried to get to work on an earlier / later model.

@martyuk does refurbed HEVAC units and knows a lot about them.

Right, as ever, here comes the cavalry. I mean it. Thankyou.
The full story on the HEVAC unit. My previous unit worked, along with the AC. The compressor always kicked in. Program demist disappeared
and the Auto/fan speed knobs fell apart. Each time I had it recharged the reports varied from wont go ahead with recharge (had the condensor and plumbing changed)
to wont quite come up to scratch. I thought I'd give it a coat of looking at as the dash was coming out. I renewed the dryer and found someone hadn't tightened the connectors up, obviously trying to do it without taking the bumper off.
I renewed the O rings on the evaporator connectors after removing it to check for leaks. The replacement control unit didn't light up at first but did so on poking a couple of knobs.
All the functions appeared. When the compressor wouldn't fire up after a proven sound system I suspected the control unit. I switched it for my "known" original. Now the screen doesn't light up at all.
I haven't got demist functions either. I'm suspecting I've done something stupid along the way. The same with the ABS and the suspension. I'm getting no faults on anything, anywhere. I know in my heart
about the ABS but the bleed nipples on the booster..............!!! After getting a hard pedal I thought I was out of jail.
If you don't mind, I'll gather my thoughts for a couple of days and come back to you all. Everything was alright until I thought I'd overhaul everything. I had a serious meltown in southern spain
so I thought I'd do something preventative. I've done that alright. I'll be working with SCUBA gear next because the whole thing's going in the bay.

On your year of car compressor is powered when HEVAC pulls relay 3 in engine bay fuse box and compressor is powered from fuse 27 via dual pressure switch. Display missing may just be blown bulbs. If your car has heated seats it should have latest HEVAC unit fitted, part number JFC102550.

As mentioned - the ABS system is normal.

The TC light will go out when the system has hit a certain pressure, as will the handbrake light - again when it gets to a certain pressure and the fluid level is reporting OK. The ABS light is also linked to pressure too (all 3 are controlled by the ABS ECU/BECM) but this one will stay on until the vehicle has gone over 5mph and the ABS ECU has done a self check of the wheel speed sensors.

AC system - what part number HEVAC controller do you have? The Thor system has the HEVAC controller drive a relay in the fuse box, which then supplies battery +ve to the compressor clutch, via the tri-pressure switch.
So things to check on that side:
Fuse F42 in the engine compartment fuse box (Feeds the HEVAC and seems to use this feed to drive the AC Compressor output)
Fuse F27 in the engine compartment fuse box (This is the positive feed to the relay contacts that actually goes to the compressor clutch)
RL3 in the engine compartment fuse box (This is the relay the HEVAC turns on when driving the AC, which then powers the compressor clutch))
Tri-Pressure Switch and wiring down near the receiver/dryer (the feed to the compressor clutch goes through pins 1 (Green/White) and 2 (Whitle/Light Green) and is turned on by a pressure switch - which is supposed to disengage the compressor if there is not enough pressure, or too much pressure in the system. These can fail, so even if you have a correct charge of gas, it won't turn the compressor on. If it is faulty then you WON'T have a connection between pins 1/2 when the system is gassed. If it needs replacing, then it can be done without discharging the system as there is a schrader valve in the pressure switch port)

I have seen a couple of times, wiring around the tri-pressure switch become crusty/corroded and break inside the insulation which can also cause the problem.

My fault finding steps would be:
1) check the fuses
2) bridge the contacts of RL3 to manually turn the compressor on. If it comes on, then the problem is either the relay or on the control side to the relay, if it doesn't then the problem is on the power side from the fuse box to the compressor clutch
3) if on the compressor side, check continuity between pins 1/2 of tri-pressure switch, and 12V on the Green/White wire. (with relay bridged)
4) if tr-pressure switch checks out, then with the relay bridges and pressure switch connected, then check for 12V at compressor
5) if on the control side, then let me know as there are a few other things to check before condemning the HEVAC controller, but most of the time the issue is the engine bay side, either a bad pressure switch, connector, or fuse.

Hope this helps,
Marty

Blimey Marty. THAT'S a reply.
I'm taking 3 days away from the enemy. I'll resume on Monday morning.
That's just the logic I require as, guess what. ATS emptied the AC system when the compressor wouldn't fire up.
On the face of it my brakes and warning lamps are all OK but weren't before I started out.
I felt when I renewed the drier the prudent thing would have been to renew the associated gubbins. By the way, I renewed the fusebox earlier this year and ommitted to mention I'd checked the fuses and switched relays before posting.
Thanks again all. Matron wants me.

Hmmm...wonder what your Matron is like. Mine's Chloris Leachman out of Mel Brookes High Anxiety

Anyway, three days in P38 Rehab will have you fixed up in no time - hope there isn't a waiting list - some members on here have their own parking spaces out front.

I can see that Cloris Leachman could appear as a fantasy matron.
But our matron is real.
Bit like Hattie Jaques.
Owch ! Damn it ! She's caught me on Landyzone.
It's off to counselling now, I fear. I hate those wire things they put on my head.
Can't wait to get back to my P38 for a bit of light relief.

Fantasy, fantasy......ooooh no, she's very real, er, possibly.
Anyway, enjoy your jolts from her volts

Just to digress.........HEVAC Control Panel.
The part number of the control unit I removed is JFC 102550
The part number of the replacement is AWR 5051
There are other codes and both units appear identical on the face and the replacement
at first performed all functions it seemed that mine didn't.
mine............................................................... replacement

G30 AC222.0 -12V IND: B............................G30-AC222.0-12V IND: G
W963910T.......................................................W963284G
Valeo 89172011 48/01..............................Valeo 69172004 24/96
land rover JFC 102550..........................................land rover AWR 5051

When I renewed the drier apart from the plumbing connections not being tightened there was a fair amount of crud in evidence.
I removed the bumper anyway to renew washer motors and spruce up rusty outiggers and waxoyled together with
mixing and matching headlamps to make a pair of good ones out of two pairs of wrecked ones. I cleaned off the contacts in evidence
and tied up dangly cables. I didn't think to check the validity of the cable cores. I know from experience that once disturbed anything can happen to anything and most probably will. I've ordered a pressure switch and tri-pressure switch and,
when I resume on Monday I'll work through Marty's logical test proceedure.
I've put the brake thing to bed, now and went to town with cleaning the EAS height sensors upon leaving yesterday morning. I went to town with switch cleaner which should do its work over the weekend. (Not WD40 I hear you screem).
Once again, thanks all for your efforts to help me.

Now..............Saturday morning and the sun's out. We get an extra treat. I'll get a blanket over my knees and get wheeled out onto the lawn.
I'll get a bacon sandwich, then, get dive bombed by the seagulls.

Regs. P.

supapete said:

Just to digress.........HEVAC Control Panel.
The part number of the control unit I removed is JFC 102550
The part number of the replacement is AWR 5051
There are other codes and both units appear identical on the face and the replacement
at first performed all functions it seemed that mine didn't.
mine............................................................... replacement

G30 AC222.0 -12V IND: B............................G30-AC222.0-12V IND: G
W963910T.......................................................W963284G
Valeo 89172011 48/01..............................Valeo 69172004 24/96
land rover JFC 102550..........................................land rover AWR 5051

When I renewed the drier apart from the plumbing connections not being tightened there was a fair amount of crud in evidence.
I removed the bumper anyway to renew washer motors and spruce up rusty outiggers and waxoyled together with
mixing and matching headlamps to make a pair of good ones out of two pairs of wrecked ones. I cleaned off the contacts in evidence
and tied up dangly cables. I didn't think to check the validity of the cable cores. I know from experience that once disturbed anything can happen to anything and most probably will. I've ordered a pressure switch and tri-pressure switch and,
when I resume on Monday I'll work through Marty's logical test proceedure.
I've put the brake thing to bed, now and went to town with cleaning the EAS height sensors upon leaving yesterday morning. I went to town with switch cleaner which should do its work over the weekend. (Not WD40 I hear you screem).
Once again, thanks all for your efforts to help me.

Now..............Saturday morning and the sun's out. We get an extra treat. I'll get a blanket over my knees and get wheeled out onto the lawn.
I'll get a bacon sandwich, then, get dive bombed by the seagulls.

Regs. P.

Click to expand...

AWR5051 is no longer available as a spare for earlier cars and the latest JFC102550 must be fitted. There are subtle differences internally. Did you check fuse 27 and relay 3? It may have been a better thing to do the checks first rather than just throw parts at it. Display not showing may just be a blown back light bulb.

I mentioned a few posts ago that I renewed the fuse box and a number of relays earlier in the year. I also mentioned that I checked the fuses and switched relays
for known and tested ones relevant to HEVAC. In ignorance, it's a reflex thing to renew parts. The auto/blower knob had fallen apart and the prog. demist had packed up. It looked awful, as well.
I bought the wrong unit, again, out of ignorance. I've paid for my error. Thanks to Marty I will be carrying out the diagnostics to which you refer, but not until Monday. I doubt this will be the last occasion
I'll have the error of my ways pointed out. Thankyou for taking an interest in my demise. I do appreciate it. Regs. P.

supapete said:

I mentioned a few posts ago that I renewed the fuse box and a number of relays earlier in the year. I also mentioned that I checked the fuses and switched relays
for known and tested ones relevant to HEVAC. In ignorance, it's a reflex thing to renew parts. The auto/blower knob had fallen apart and the prog. demist had packed up. It looked awful, as well.
I bought the wrong unit, again, out of ignorance. I've paid for my error. Thanks to Marty I will be carrying out the diagnostics to which you refer, but not until Monday. I doubt this will be the last occasion
I'll have the error of my ways pointed out. Thankyou for taking an interest in my demise. I do appreciate it. Regs. P.

Click to expand...

Did you fit the correct fuse box? Needs to be YQE103410 for your car.

Affirmative.New from Island 4x4.(I'm keeping Island on its stilts single handedly) Just to clarify what I'm attempting here. A perusal of my threads and posts will show that I had problems big time over wintering in southern spain. My object over this "summer" is to thoroughly overhaul, as much as I'm able, all that I know is due for service (such as the fuse box should have been and wasn't) and all that makes sense to me as a non-expert in order to make the round trip this winter, confidently. The airconditioning has been recharged every two years, for example, but not quite coming up to scratch. The EAS has always been OK but not quite up to scratch. The irony is, everything worked. Until now. I've done what I thought was sensible diligent preparitory maintenance and come unstuck. I'm aware that I've got an old car on my hands, fifteen and a half years to be exact, but, the undercarriage is sound and waxoyled every year and the body panels are in perfect shape. Recovery in Spain, provided by anyone, is not what we get here with RAC Arrival-car and caravan. To get repatriated the exercise depends on equating to the value of the car or less. Their idea of what my motor's worth will probably differ somewhat from mine. If it doesn't measure up, they scrap it where it is. So,I know everyone's non-functioning car brings about its own consequences but, my predicament simply adds to me hitting the panic button prematurely, rendering forth on Landyzone and especially buying parts hastily, later to rue. It also contributes to the whimpering, dribbling, nodding wreck you see here in the west wing.

AWR5051 is the last version HEVAC for the GEMS models - and is listed as being a superceded part number for AWR1012.

I believe that it is designed to drive the compressor clutch directly - and this when the wiring upgrade was done on later GEMS models, they needed a power resistor in line to fool the ECU into thinking that it is actually driving the compressor, when it is actually just powering a relay.

I don't think it will work properly with your vehicle as the vehicle wiring was changed to include the relay in the fuse box. So you would ideally need a JFC102550 unit for it to work as intended for your model year, and not throw a fault.
If you need any of your HEVAC units serviced, then I offer fully serviced units on exchange, or can service your original unit(s) if you have things like autobiography wood trim...

I personally don't think the AWR unit will work properly - it will most likely shut off the compressor when you try to run it as it won't detect a load. As I mentioned, there must be a change in firmware on the later units with that error being programmed out to allow for the change in vehicle wiring.

I would check the wiring etc from the fusebox, pressure switch and all that first - because if there's an issue there then it won't matter what the controller is trying to do - and will also just confuse matters even more

If the under bonnet wiring checks out, then let me know, and I can help you sort out the options for getting a working controller that is compatible with your vehicle wiring...

Hope this helps,
Marty

martyuk said:

AWR5051 is the last version HEVAC for the GEMS models - and is listed as being a superceded part number for AWR1012.

I believe that it is designed to drive the compressor clutch directly - and this when the wiring upgrade was done on later GEMS models, they needed a power resistor in line to fool the ECU into thinking that it is actually driving the compressor, when it is actually just powering a relay.

I don't think it will work properly with your vehicle as the vehicle wiring was changed to include the relay in the fuse box. So you would ideally need a JFC102550 unit for it to work as intended for your model year, and not throw a fault.
If you need any of your HEVAC units serviced, then I offer fully serviced units on exchange, or can service your original unit(s) if you have things like autobiography wood trim...

I personally don't think the AWR unit will work properly - it will most likely shut off the compressor when you try to run it as it won't detect a load. As I mentioned, there must be a change in firmware on the later units with that error being programmed out to allow for the change in vehicle wiring.

I would check the wiring etc from the fusebox, pressure switch and all that first - because if there's an issue there then it won't matter what the controller is trying to do - and will also just confuse matters even more

If the under bonnet wiring checks out, then let me know, and I can help you sort out the options for getting a working controller that is compatible with your vehicle wiring...

Hope this helps,
Marty

Click to expand...

Interesting. So the wiring change in the later GEMS essentially brought them into line with the diesel and THOR setup.

Grrrrrr said:

Interesting. So the wiring change in the later GEMS essentially brought them into line with the diesel and THOR setup.

Click to expand...

If your car has ATC and heated seats it does not matter which part number you enter. None are available other than JFC102550 which supersedes them all. Mine should have an earlier version fitted, does not have relay 3 yet JFC102550 works quite happily without any wiring changes that i am aware of.

Who are these masked men? BTW, it's just dawned on me that there's an accolade system on here. Sorry if you chaps have gone to town to help me and are owing "likes". I'll see if I can apply them retrospectively.
The main problem here is the nut on the mouse and the nut behind the steering wheel. Before I started my overhaul the AC worked and the suspension worked. I've double checked the fuse box this morning even though I threatened to blank her till Monday. Indeed, QYE103410 Pet. I ran a compatibility test on a certain party's well known auction site and, indeed AWR5051 was noted as unsuitable. My clanger. I've learned (God I'm too old for all this brainpower) that if an AC installation is non functional no one I've spoken to will leave the refridgerant in. For test purposes the system has to be filled with oxygen free nitrogen. I've found someone who'll leave it in after he's seen evidence that the solution is naught but a control issue. Tomorrow morning, having printed out Marty's gospel , I'll carry out what tests I can before the pressure switches arrive. The compressor has never not fired up, right up to me starting this fiasco. As for the EAS. I trawled through all three levels a few times after a couple of days of switch cleanering. It raised and fell squarely. I tried the Storey Wilson reset before posting here some days ago and all the the things he preaches on his video failed to happen. When I got the height readings they were all over the place. When I tried to write new settings and SAVE the inputs simply changed to the settings above as read. That's another back to the drawing board. I also tried the hawkeye reset. What that does I've still to find out. I'll go and poke a few likes in if I'm able, now. We all have to go to chapel now.

If your height settings are all over the place then it won't save them because they are outside the accepted norms.
When you read the ACTUAL heights, the fronts and rears should be within 5 points side to side.