Thread: P38 Rangie Air Con Problem ?

Check the 2 yellow blower relays in the main fuse box. If too hot either of these can fail intermittently. If one faults the cooling efficiency drops drastically.

My P38a exhibited much the same symptoms.
Intermittent 'testbook' symbol accompanied by loss of efficiency.
Finally the 'testbook' symbol remained on.
The fault ? Burnt out blend motors.
The cause, failure to maintain the pollen filters correctly causing debris to lodge in the system.
While the dash was dismantled we took the opportunity to replace the heater 'O' rings.
As your 'testbook' has illuminated a fault will be logged in the hevac module. A quick check with 'testbook' or similar will give you a read out on your problem.
Hope this helps !

Originally Posted by ivery819

My P38a exhibited much the same symptoms.
Intermittent 'testbook' symbol accompanied by loss of efficiency.
Finally the 'testbook' symbol remained on.
The fault ? Burnt out blend motors.
The cause, failure to maintain the pollen filters correctly causing debris to lodge in the system.

Sorry old son. Failure to replace the dirty and clogged pollen filters will have no affect on the blend servo motors. There is no way they can. Unless of course someone has removed the filters and something has jammed the flaps.

A lot of people also believe that clogged pollen filters can cause the blower motor relays (RL6 and RL7) to fail. Again, I disagree.

If you block the inlet side to blowers, then the fan blades stall and the motors actually draw less current. This reduces the current through RL6 and RL7. Also, it only ever seems to be RL7 that burns up together with the fuse box.

What Jezzaol needs to do is have the fault codes read. There are numerous causes of the chequebook symbol being illuminated.

Jezz, you say the air con is still working but at reduced efficiency. There is a possibilty that the connector to the blower motor is faulty. This is a known problem on early cars. Mine had it and exhibited the same symptoms. There is a TSB on it. I have described the fix with photos on the RangeRovers.Net forum but I can't access that from here to give you a link.

Another possible cause is the heater core temp sensor on the heater pipes - another known problem child.

I'm afraid that you can throw a lot of money at the HEVAC if you don't have the fault codes read.

Thanks again,

That link would be good !

There is a TSB on it. I have described the fix with photos on the RangeRovers.Net forum.

I'll look it up when I get home.

Jezzaol,

Unless you can get someone to check for free I would not waste any time or money on fault codes.

Apart from often being misleading as to the cause, there may be old codes stored there which were never cleared after previous work and these are going to send you off in the wrong direction.

The problem you describe is most likely one of the blowers not working. 99% of the time it is failure of blower relay 7. When this overheats and fails the book symbol comes on (but will go off again when fixed) and all appears normal but airflow from the vents drops off and becomes noisy.

Despite what you'll read on the interweb the aircon is usually simple to fix but I won't recommend anything else until you've checked this.

Ron
I am only relaying my own experience in the hope that it may be of some help!
The pollen filters disintegrated and the bits lodged in the ducts and flaps !

We also suspect that in the process of a previous filter cleaning bits of debris were allowed to drop into the system when the filters were removed. This was evidenced by bits of what appeared to be dried gum leaves found near the blend flaps.

BTW The main plenum filter was also absent.

If he reads his faults he will get the answer.
I totally agree with you :
"I'm afraid that you can throw a lot of money at the HEVAC if you don't have the fault codes read."

Originally Posted by P38ace

Check the 2 yellow blower relays in the main fuse box. If too hot either of these can fail intermittently. If one faults the cooling efficiency drops drastically.

thanks for your postthe wife's blower fans are now working again......

but now the air compressor wont which on so no cool air

any suggestions ??