Thread: Heater O-ring and blend motor

In way of a cross reference to another good article on blend motor tests this has helped me find out which blend motors worked.

In addition, because I had the instrument shroud out still (but instruments in), I was able to put my finger down and feel the distribution motor vibrating as I changed the head/feet/windscreen setting on the air con controller.

I was surprised that I could hear the recirc flaps moving when the engine was off. Very easy to tell that recirc and distribution motors are working using the air con controls with the ignition in position 2.

However, I still have no heat, and I could not feel the temperature flap motor vibrating when I turned up the heat with the engine running. I can only assume that the temp blend motors (both sides) are cactus. Next step is to have -another- crack at getting them out and cracking them open.

Need heat before winter! shmbo will not be impressed

Although I think you'll be OK today ....

I cut the Vertical Duct today and performed the changeover.
The dreaded Book Symbol is now gone, and the air conditioning is functioning a lot better.

It's still not "Icy Cold" which I'm not certain relates to the Level of Gas ete in the system... I'd love to have a link to "Factors dictating Air-Con" Performance or a similar document so I could understand it more.

Regards
Heath

Hi Heath,
What year/model is your P38?

If it is the Gems (up to 1999) Check to see if the heat shield is still there at the back of the air con. compressor. It should be a small peace of checker plate about 1/2 inch from the rear of the compressor between the compressor and the headers.

If it is missing your compressor has to work very hard to give cool air let alone cold air.

I've got 2 x P38 Range Rovers and I can't see any such Heat Shield from what I can see... Do you have a Picture/Diagram at all?

Originally Posted by BusinessConnected

I cut the Vertical Duct today and performed the changeover.
The dreaded Book Symbol is now gone, and the air conditioning is functioning a lot better.Heath

I am in the same boat, yesterday I too cut the vertical drivers side duct (with a rope saw) and got access to the drivers side temperature blend motor. As suspected, if I move the blend flap behind the motor arm with my finger it moves freely and I get very warm or very cold air coming out of the drivers dash air vent! Happy, that means all the heat and cold systems are working and confirms that it is just the temp blend flap motor mechanism. I cracked open the cigarette sized box and all looks good; no broken teeth on plastic sprockets, all the tracks on the circuit board are in tact, but it doesnt move if I adjust the temp on the climate control panel. Now I have to work out if the small motor is broken, or the HEVAC computer is not sending it a current to request it to move. Might need to hit the ET section on RAVE to find the electrical voltage the units expects under certain conditions and measure with the multimeter.

For your information when I opened up mine they looked fine as well... just not working electronically. I replaced with New Blend Motors and all was well.

Originally Posted by BusinessConnected

For your information when I opened up mine they looked fine as well... just not working electronically. I replaced with New Blend Motors and all was well.

Thanks, good info.

I just desoldered and tested the small motor on the blend motor assembly. When applied with 12v, it turns fine in both directions. It makes me wonder what part of that simple assembly is not working? The variable resister seems to change the voltage when turned, and the only other thing on there is a tiny capacitor.

I am happy to get a new motor and fix the problem, but I will have a crack at outsmarting it first <it is at this point that I normally break something else>...