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Discussion Starter #1
OK - I have successfully removed my entire dash, replaced the leaking heater o rings and am now attempting to figure out what's going on with the blend motors. My initial idea was to just buy new ones and replace - but I thought first I would see what I could find out about the old ones. So I took them apart and found the gears to be perfect on all three - and I checked the little flat thingys inside that sometimes get rounded and create a short - they were nice and flat. So I put the control unit back in place along with the airbag and instrument cluster and plugged in the motors to just see if one of them didn't respond to the control unit.

None of them did! So my question is - shouldn't I have been able to see all of the motors turning their little spindles as I changed the settings on the control unit? Did they somehow know they weren't screwed in to the flaps? Is this a sign that my control unit is no good? I noticed the book symbol remained - even though the motors were free to turn. Is there another test that would tell me that the motors are indeed the problem? I would hate to replace them if they are perfectly good - although I suppose at 130+K I should replace them anyway...

Any thoughts would be appreciated! Thanks.
 

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1995-2002 Range Rover P38A
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Hi

The blend flap motors behind the dash (not to be confused with the recirculation flaps fitted on the blower units) do have a position feedback signal towards the ECU. It is very often this position feedback signal provided by a potentiometer mounted inside the housing that fails and will not report back the position towards the ecu anymore. On every start up the flaps are moved the whole range from fully open to fully close with the ECU monitoring and registering the end positions which it can see because of the amperes towards the motor are rising when the motor stalls. After this self test the system starts working. If any problem is detected the ECU shows the book sign and might stop operating the flap that has failed the test.

So after start up the flaps should all move. If they don't there might be a problem with the carbon brushes. I remember that a member from Norway if I am not mistaken has written up a procedure complete with photo's to sand the worn off carbon brushes back in shape. By doing a search you should find it.

If you have access to a diagnostic system you can have the system reset all fault codes and then see which ones will get triggered the moment the book symbol shows up. This will narrow down your search of which unit can be at fault.

In general the blend motors are unrelaible pieces of junk that are very much overpriced and in my opinion a reason why LR should never ever incorporate Valeo stuff in any of their cars ever again. From LR mechanics I have received feedback that they only last about 4 years before they are starting to give problems. So if you want piece of mind and the high price is no obstacle it is best to change the whole set.

Here in the tropics nearly all cars that are here have the blend motors disabled and the system set at 100% cooling all the time. It is not very usefull to have a climate control system with heating possibilities when ambient temperatures at night are 24 degrees celsius and up to 48 degrees celsius on a warm afternoon.

Regards

Jos
 

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Discussion Starter #3
Thanks for the reply Jos. Unfortunately - here in the Pacific Northwest - I need those darn flaps to work! 100º in the summer (F) and below freezing in the winter. I did the sanding on the brushes - they weren't bad to begin with. I just thought when I plugged it into the control unit that I would see the spindles turn as it went through the self diagnostic - where you mention that it moves everything all directions. But nothing moved at all - none of the three motors responded. So my concern is that even after replacing them with new - that they still might not work due to another problem as yet undiagnosed. I guess I will order the new ones (yeah yeah - need them anyway) - and try that test again. I don't have access to any equipment that would read the codes or clear them either - unfortunately. Just don't want to put the dash all back and find that they aren't working!
 
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