P38A blend motor

Then I'd definitely recommend you start afresh. If the PO didn't chop too high then you should have enough cable on the motors if you gently pull each cable vertically down through the two retainers on the heater unit. The correct pins and connector are here:

https://www.ebay.co.uk/itm/AMP-16-W...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

You can find the connector cheaper on its own, but it's the correct pins that are the important part

right i'm really struggling, its always the little things!
theres plenty of info on here and other places on the interweb on how to get to the passenger blend motor. they're all similar in stating the dash veneer above the glovebox can be prised with *gentle* persuasion starting at the left and working to the middle of the car.
My dash has been out previously, probably for the mobile phone fitment and I'm wondering if the veneer strip has been glued back in place. I can get a suitable tool under the strip and can 'feel' where the 1st 2 pins are but i'm exerting what feels like edozens of pounds force and get the idea if i get more brutal, things will start snapping.
any advice? whats the chances i will actually break the pins that fix into the frame?
thanks

Well - it does need quite a pull, to be sure. Yyou're best off sticking multiple nylon trim levers in there - but use them as wedges, not levers. The backing to that trim is aluminium, but not majorly thick. The pins are also aluminium, which push down into plastic rivet outers when fitting - it's actually a very effective system. IIRC there are four or five pins - you're aiming to get c. a 1cm gap on each and then it shd just come out. In theory the pins ren't going to break, as they're just being held back by plastic corrugations- but do try and make sure the trim itself is not being used as a lever

romanrob said:

Well - it does need quite a pull, to be sure. Yyou're best off sticking multiple nylon trim levers in there - but use them as wedges, not levers. The backing to that trim is aluminium, but not majorly thick. The pins are also aluminium, which push down into plastic rivet outers when fitting - it's actually a very effective system. IIRC there are four or five pins - you're aiming to get c. a 1cm gap on each and then it shd just come out. In theory the pins ren't going to break, as they're just being held back by plastic corrugations- but do try and make sure the trim itself is not being used as a lever

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Cheers, I'll put some more sweat into it! Helpful to know the pins aren't plastic. Not hoyt any fancy trim removal tools but will try my best and won't just pull on the free end of the trim

Ok revisiting my hevac saga
The drivers side is easy so concentrating on that for now. Diag says both left and right blend motor short circuit to positive and distribution in stall position.
The drivers blend motor works perfectly. Power to the motor and it spins freely in either direction, the pot sweeps nice and smoothly.
The cable to the blend motor tests fine, no apparent breakage or other damage and goes from fully open to fully closed etc when i all for calibration. Surely it wouldn't do this if there was a short?
The distribution flap appears to work fine in normal operation.
Do i actually have a problem with the hevac unit and not the blend motor? I don't know how to test that though I've seen folks do it on YouTube

Just had a thought, could the motor inside the blend motor be worn and drawing too much current, so it still works when connected to 12v but the hevac sees to many amps and logs a short?
Edit. Measured approx 0.06A

kermit_rr said:

Just had a thought, could the motor inside the blend motor be worn and drawing too much current, so it still works when connected to 12v but the hevac sees to many amps and logs a short?
Edit. Measured approx 0.06A

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I cannot remember, but I don't think the motors are 12 volt.. Could well be wrong on that it's a while since I had one apart. A lot of HEVAC problems on my project car were due to a bad earth to the HEVAC

12v seems to be the consensus. Hadn't considered a bad earth, certainly worth pursuing, cheers.

You can shift the motors with a 9v battery, which is more like 7/8v anyway. 12v is supposed to kill the motors, but I have neither proved nor disproved the theory. Did the hevac work previously?have you now checked the pinning at the hevac connector, Kermit? Are all the motors moving back and forth on start-up?

My recent experience for what it is worth. I had more or less the same experience as you, particularly with the distribution flap motor. All worked fine off the vehicle, flaps moved by hand OK, but fitted up, the unit stalled and threw an error and book every time regardless. If I didn’t help the motor by pushing and pulling the flap gear then it stalled.

The motors fitted were Britpart. I bought a set of Valeo motors and spliced in the distribution flap motor. All good, no more problems, plenty of power to move the distribution flaps from one end to the other etc. and no more errors. I can only conclude that the Valeo motor has a lot more torque than the Britpart motor. I know the Britpart motor was reasonably new as it had been fitted about 15 months ago.

On my test rig i use 7 volts for testing the motors. They are 12 volt motors but travel too quickly and can be damaged unless in situ. Motors can be stripped out disassembled and carbon deposits that cause shorting removed to return them to working order.

The hevac is sending 6.94v to the blend motor.
There seems to be next to no resistance from the earth pin on the hevac to another part of the chassis ground.
When i put the motor in place and turn the ignition on, it goes one way until it reaches the limit of travel, brief pause then goes the other way to the limit and stops. If i turn the ignition off and on, it will repeat the 2 cycles.
If i use nanocom to calibrate, only the distribution motor moves. If i force either the left or right blend motor to move, they do not, but the distribution motor moves briefly. I can feel the motor buzz and also feel the mechanism move with my fingers so i know I'm not mistaken

kermit_rr said:

The hevac is sending 6.94v to the blend motor.
There seems to be next to no resistance from the earth pin on the hevac to another part of the chassis ground.
When i put the motor in place and turn the ignition on, it goes one way until it reaches the limit of travel, brief pause then goes the other way to the limit and stops. If i turn the ignition off and on, it will repeat the 2 cycles.
If i use nanocom to calibrate, only the distribution motor moves. If i force either the left or right blend motor to move, they do not, but the distribution motor moves briefly. I can feel the motor buzz and also feel the mechanism move with my fingers so i know I'm not mistaken

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After it does the cycle on ignition it is supposed to go to the selected position as controlled by the left and right heat selector buttons.

wammers said:

After it does the cycle on ignition it is supposed to go to the selected position as controlled by the left and right heat selector buttons.

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It did this for a while, when i last attacked the problem but only worked for a few days and was always on the cool side. Then it went back to not working at all

Reading this thread is depressing. I have to look at mine at some point.

Right. If at first you don't succeed, cheat!!. I applied voltage to the passenger blend motor, while in situ moved it both ways briefly and it's sprung into life!! Result! No book symbol until the drivers one does its cycle.

kermit_rr said:

It did this for a while, when i last attacked the problem but only worked for a few days and was always on the cool side. Then it went back to not working at all

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Then the only thing it can be if the blend motors cycle is that the HEVAC is not sending the signal to move them to the preselected position. If they are at 50% when the ignition is switched off they should cycle then return to 50%, sounds like the HEVAC is duff.

wammers said:

Then the only thing it can be if the blend motors cycle is that the HEVAC is not sending the signal to move them to the preselected position. If they are at 50% when the ignition is switched off they should cycle then return to 50%, sounds like the HEVAC is duff.

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I'm guessing there's an ECU associated with the HEVAC?

Tenebreaux said:

I'm guessing there's an ECU associated with the HEVAC?

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There is an ECU in the HEVAC.

Bit more investigation...
If i set the passenger blend motor (now working) to 100% and also the distribution motor to 100%, the value registered on nanocom is 100 and 105 respectively. If i manually turn the pot on the driver side motor, the value goes from 0-92
I'm wondering if this is the problem? The hevac doesn't see a high enough value and marks it bad?