P38 Heating and cooling issues

[jnmorgan]

I am trying to get my 1998 Land Rover Range Rover ready for my son's senior year in HS here in Charlotte NC. My pressing issue is heating and cooling. Both under dash blower motors have been replaced and will operate when the HEVAC control knob is turned all the way up, but here are the problems:


No heated air - just air blowing
No cooled air - just air blowing
The air only blows on your feet and cannot be adjusted to the dash vents even when the HEVAC buttons to switch location from feet to dash are pushed.


Any help would be greatly appreciated

Thank you,
Nick

[prelude]

Looks like it might be trouble with the HEVAC blend motors. Do you have the little book sign lit on the HEVAC?

The HEVAC has 3 motors, 2 to blend the air on each side (more or less heat, the cold air is always the same) and a single motor that selects the vent outputs. All three are connected through the same connector on the back of the hevac, in very rare cases it could be that this connector is not connected or broken. It is more likely that all 3 motors have seized, are broken, etc. They are a common fault.

I would start by checking the on board computer for errors if you have the possibility to check the error codes. If not, take the centre piece out so you can get to the back of the hevac computer and test the motors manually with a power supply and an amp meter. You can find a pinout below for examplehttps://www.stockholmviews.com/p38/hevac/blend-motor-diag.jpg
Disconnect the plug before testing of course :)

Once you have done that, we can see what's what and take it from there.

Best case scenario: stuck motors and a bit of 12v power will free them up.
worst case scenario: the dash needs to come out to replace the motors. :(

Cheers!
-P

[TheTree]

Hi

Just one comment , the dash does not need to come out to do the blend motors ;)

Steve

[prelude]

True!

I just like to work with some space so I guess it did not cross my mind to mention ;) but you are right, there are ways around having to pull the dash!

-P