P38 HEATER PROBLEM.

Hi, my mate has got a prob with the heater in his P38, the heater blows hot air on the passenger side, but cold air on the drivers side.We removed some of the interior panels to look at the electric operated blend motor on the side of the matrix, and when the buttons are pressed to select heat to the windscreen/floor etc, the motor is moving and the air,all be it cold, does come out of whatever is selected,but why is it cold? anyone know, thanks in advance.

possibly the blend motor potentiometers

http://www.rangerovers.net/repairdetails/blendmotor.html

Blend motor is not working. There are two motors on the right hand side the top one is the distribution motor which seems from what you say to be working. Be lucky that is the usual one to fail first. The lower one is the bend motor that controls heat blending. it has failed.

thanks,for all the replies, since I posted,we have removed the blend motors. The susspect one, when a power supply is conected to it (brown and black) wires, the motor runs, so why is it not working when fitted? could it be the potentiometer, as mentioned above, or if that is at fault, would the motor run at all?

sideways derek said:

thanks,for all the replies, since I posted,we have removed the blend motors. The susspect one, when a power supply is conected to it (brown and black) wires, the motor runs, so why is it not working when fitted? could it be the potentiometer, as mentioned above, or if that is at fault, would the motor run at all?

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Motor will still run. But pot would give no feedback as to position. So it would come up as a fault on diag. When the ignition is on and engine running. HEVAC does a self check. It powers each motor in turn to check for feedback. If the pot does not give positional feedback, the ECU does not know where the unit is relative to where it should be, according to present HEVAC settings. It will shut that unit down and put the book symbol up on the HEVAC. If you have or know someone with Nanocom you can try cycling the motors or you can try cycling the motors with the HEVAC controls sometimes this works. But the pots for what they are expected to do are reported to be pretty lot cycle life items and do fail. There are postings on the net of how to change them and what to fit as replacements.