VT Air Con electric clutch won't energise

[Darren D]

Hello all,

I have a VT V6 in which the air conditioning won't work.

I have traced it to an electrical fault whereby the electric clutch on the compressor won't energise. If I hot wire the clutch it is fine, if I bridge the relay it is fine, but somewhere between the air con switch and the relay I have an open circuit (swith light comes on when pressed).

Is there a fuse in there somewhere? I have checked all the standard fuses and they are all fine but I couldn't actually find one dedicated to the air cond system.

Any relevant info guys?

Thanks in advance,

- Darren

[Tsunamix]

The aircon has a pressure sensor and maybe a temp sensor. The pressure sensor checks the pressure in therefrigerant tank to make sure its not too high. When the pressure is high enough the clutch de-energises, until the pressure has drained enough. I think that the reservoir slowly releases the refrigerant gas into the heat exchanger to cool the air flowing through. In some cars its actually pumped, not pressure bled. I dont know what it is in the case of your car.

If that pressure sensor is faulty, the clutch wont energise (reading too high a pressure continuously).

There might also be an air temp sensor that works in conjuntion with the pressure sensor, so that if air temp is cold, and pressure is moderate, it delays the clutch energising. That is oprobably controlled by the BCM.

[pablo]

Non or very low refridgerant gas also will stop the cutch from kicking in.

[dave0103]

same thing happened to my vt recently i was told thet the original compressor clutches go quite regulary and the cheapest way out is replacing the compressor, which is what i did. Bought one on ebay brand new with drier for 380

[vt_lover]

I’m sorry if this comes over as rude but....
TSUNAMIX where did you get that info from??? I have been a refrigeration mechanic for 12 years and have yet to come across a system with a "reservoir" or a system that doesn’t rely on the compressor to work, even if there is refrigerant "slowly bleeding" I just don’t like it when people give BOGUS advice that’s all.

[Darren D]

Thanks for the replies.

Doesn't sound like a home fix, off to the air cond place I go with wallet in hand.

- Darren