Blend motor doing funny things!!!

Hi,

I had similar issues with blend motors.....someone on here posted a link to this guys page (See Below), and it is very helpful. I replaced the pots in my motors, and they are fine again now. (I also purchased new ones, before I read about fixing them). The pot (potentiometer) is what provides feedback to the Hevac ECU on the postion of the motor.....the carbon track wears away, and the feedback resistance goes all over the place.

Range Rover P38 Maintenance repair improvements and tips learned by experience by ownership.


I have got heaps (50) of replacement pots to suit these if you need any......I'd happily post some to you for nothing if you want to give the repair a go.

Hope that is of some help.

Regards,

Bruce

Quote:

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Originally Posted by RR P38

If you dont want to buy a new fuse box $$$. You can actually repair it.
With the heat the relay pin receivers de solder and drop out.
If you have a decent sized soldering iron its not that hard to fix.
Araldite can be used to secure the receivers in place.
The whole thing is seriously heavy duty copper and well repairable.
I repaired mine about 6 years ago and have had no further problems.
The only evidence of a repair is a slight crack and some Araldite under the relay which is not visible with the relay in place.

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I managed to source a good second hand fuse board for around $100 From the UK. I installed it today and guess what.......the blowers are working again....yeay... But the blend motor remains to be fixed. I still have the old board, and might have a crack at repairing it in the future as spare.

Quote:

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Originally Posted by brucep

Hi,
I had similar issues with blend motors.....someone on here posted a link to this guys page (See Below), and it is very helpful. I replaced the pots in my motors, and they are fine again now. (I also purchased new ones, before I read about fixing them). The pot (potentiometer) is what provides feedback to the Hevac ECU on the postion of the motor.....the carbon track wears away, and the feedback resistance goes all over the place.

Range Rover P38 Maintenance repair improvements and tips learned by experience by ownership.


I have got heaps (50) of replacement pots to suit these if you need any......I'd happily post some to you for nothing if you want to give the repair a go.

Hope that is of some help.
Regards,
Bruce

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Excellent input! I suspect the same thing for my temp blend motors. I would love to give that fix a go, as the most difficult part about replacing the blend motors is the routing of the cables from what I can see as a opened the dash to do the job.

Where you able to get the pots using the same part numbers as in the stockholm views site or are the aussie suppliers different?

Thanks!

Hi,


Yes, the Piher PT15NV-10k is the part number. I had trouble getting any locally, but found Rockby Electronics had the same trimpot, but with a thumbwheel pushed on.....it is very easy to press the thumbwheel off - it's just a manufacturing option on the standard PT15NV pot. They are 30 cents each - you must buy min 10 pcs.....a very expensive fix!! Here is a link:

Results Page

Regards,

Bruce

Blend motor all fixed. Have Air conditining again.........y:Deah!!

Quote:

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Originally Posted by brucep

Hi,

I had similar issues with blend motors.....someone on here posted a link to this guys page (See Below), and it is very helpful. I replaced the pots in my motors, and they are fine again now. (I also purchased new ones, before I read about fixing them). The pot (potentiometer) is what provides feedback to the Hevac ECU on the postion of the motor.....the carbon track wears away, and the feedback resistance goes all over the place.

Range Rover P38 Maintenance repair improvements and tips learned by experience by ownership.


I have got heaps (50) of replacement pots to suit these if you need any......I'd happily post some to you for nothing if you want to give the repair a go.

Hope that is of some help.

Regards,

Bruce

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Bruce, that's a great reference site; I've been looking for info on the blend motors as I'm planning to 'have a go'

Where did you source the replacement pots?

Jonathan

Hi,

I got them from Rockby Electronics. If you PM me an address I'll be happy to post some to you.

Regards,

Bruce

You can test the operation of the pot on the blend motor assembly. You put the black multimeter probe on the top leg and the red on one of the other two legs. When the pot's wheel is turned the pot should vary the resistance from between 0 to about 10.5. This is as tested on a new pot and also the pot installed on my (not working) blend motor. When you switch the red probe to the other leg, the figures are the same in reverse. Presumably if the carbon track was worn you would get some other reading.

Bruce kindly send me some pots, but since I noticed this before I installed them in the blend motors, I figured that it wasnt the pots that was causing mine to fail so I continued and replaced all three blend motors. I have hot air now (and cold) but the !book symbol remains.