How to test the A/C relay

[JBurer]

When I purchased my 964 Turbo, one of the items to look into further was the air conditioning. With some time off from work coming up, I thought I might look into this now, before the Georgia summer is upon me.

The compressor is not seeing power, so I am thinking the first place to check is the A/C relay. Part below -

Pelican Parts - Product Information: 811-951-253-M100

Can anyone walk me through how to verify if the existing relay is the problem?

Also, with this being a "double relay" (controlling both the blower motor and a/c), is it possible for just one of the two accessories to be not getting power? Said another way - if the relay is the source of the a/c problem, would I be having problems with the blower motor as well?

Thanks,
John

[computamedic]

The relay you mention is identical to the relay used for the oil cooler (and, indeed, for the rear blowers too) so a simple swap would confirm your thoughts.

In reality it's unlikely to be the relay as the a/c system has a pressure switch up near the evaporator which prevents the compressor being activated if there is insufficient gas pressure in the system. Before spending money on parts it's probably worth getting a a/c specialist to do a pressure test and a re-gas if there are no leaks and see what happens from there.

Regards

Dave