Thread: Aircon compressor clutch not working! Ideas?

[quote=MacMan]Hi all,

Just when I thought I was having a good run: the aircon compressor clutch is no longer engaging and what <span style="color:red">little cooling</span>




<span style="color:blue">if you had only little cooling and now its gone...you may have been low on gas....
if the pressure is too low it wont switch on to avoid it self destructing...

i think you may have a leak somewhere.....
get your pressure checked so you know if you have gas in the system.....</span>

Within the wiring for the air compressor there is a switch which if you are low on gas as Defender Zook says will not complete the circuit to supply 12V to the clutch

AHAH! Sounds like it is highly feasible.

I have the service history for this car and from what I can see, there was a TX valve in the aircon that was replaced as a 50/50 warranty/customer cost. LRA contested it, the original owner disagreed and thats where they met. The system was depressurised at that point for the repair.

Then in the late 90's there was a leak and some hoses were replaced. I bought the thing in May last year and it was regassed again (this time with dye in the refrigerant) just prior to purchase.

I noticed about 4 months ago that it was not as cold as it used to be and did some reading. There were bubbles in the sight glass and I decided not to wash the engine bay to make it easier to pick up the dye under the UV light or whatever the aircon guys use.

Yesterday I noticed that one of the hose connections at the fittings on the firewall (I guess it must be the high pressure line) was fuzzy with dirt and oily. Given that the compressor oil dissolves in the refrigerant, am I likely to be correct in assuming that there has been a leak at that location and the refrigerant has evapourated leaving the oil behind? There is nothing else in the vicinity that would spray, spin or drop oil onto that joint.

Thanks guys!

Just had another thought - if the pressure switch is IN the compressor, the leads feeding it, the clutch relay and the fuse should all still be powered, no?

The WSM is very patchy on detail with this one...

<span style="color:blue">to distinguish between the high and low pressure pipes....

the thin is the high pressure.....
and the thick is low pressure.....


and you will need to have the problem fixed before getting it regassed....
bubbles in the sight glass tell you that you are low on gas....

a job for an auto electrician.....you need to be licensed to work on aircons...</span>

I wasn't planning on trying it myself, but I hate paying for work when I don't have a full understanding of the problem.

So do you know where the pressure cutout switch is? In the compressor itself or somehere else in the system?

Can I suggest moving to a cooler climate Ah hahaha

Oil on condenser fitting = gas leak

Take it to a quality repair outlet

Cheers Blythe

The pressure switch will most likely be on the refrigerant lines in the engine bay. Should be just two wires on it. Short them together, if it fires up like normal then you are low on refrigerant.