A/C problem

[mark wild]

Hi

First ever post, but need assistance asap, tested ac unit today on a 1998 996 2
didn't blow cold thought it needed refill, took it to a ac specialist about 6 pm on route home chap stayed open thinking it would be a simple job however after pressure testing the system and refill it failed to blow cold, he did say bring back and he'll look at it however he also told me it could be the ac clutch not engaging or something as simple as a relay, could someone assist me in where i might find this relay to test or where to test elsewhere. i can hear the revs increase also.

thanks mark

 

[Richard_Hamilton]

Mark!

If the compressor isn't running there are 4 possibilities I can think of:

1. The system is low on regrigerant - this is by far the most likely, even after what you have had done. The front condensers are a common problem. Look for refrigerant (usually green) under the front rads, or along the pipes running under the driver's side sill.

2. The pressure switch is faulty - this is located next to the filling points.

3. The relay is faulty - this is located on relay support 2, under the carpet panel behind the rear seats (on a coupe). See attached.

4. There is a wiring fault - I don't suppose the engine has been removed, or any recent work in the engine bay?

 

[mark wild]

Hi Richard,

No i cant see any green liquid either at the front or the door sill, i found the relay and without knowing what voltage it throws all i can say is that its clicking when i engage the a/c, what i have noticed is the compressor outer fly wheel isnt spinning, however the rest of the system seems as mentioned before to be functioning ok revs increase etc. also not sure if engines been removed but it does have a FPSH so i'm thinking take it back to them.
does this make any sense or the problem any clearer.

BR and thanks for the last post.

 

[Richard_Hamilton]

If the relay clicks, it sounds like it is getting the signal to engage the compressor. There is a single wire from the relay to the compressor clutch (green & yellow). You could check that there is 12v on that pin of the relay when you engage the A/C, and if so you could find the connection at the compressor end to see if there is 12v there too. If power is getting through, then it must be the compressor clutch. (No. 5 on my list above) []

 

[mark wild]

Thanks richard,

I can see the compressor wiring however its covered in a silver heat shield i presume the other goes to the nearest bolt as an earth, trouble i have is that i cant see the relay housing due to the roll bar support in the way can this be removed easily to alow me access to the relay as per diagram at the mo i'm just squeezing my hand through the gap.

Regards Mark
ps thanks for the quick reply

 

[Richard_Hamilton]

Try to find it at the compressor end. It is a single (black) wire coming out of the compressor, going to a single connector, where the green/yellow wire joins. See if it is getting 12v there.

 

[mark wild]

Richard

I'll look tomorrow now, but will keep you posted on how i get on. hope its might be of use to others, may i say to any prospective porsche owners this site is not be be missed. thanks for your assistance.

BR Mark