Hi,
I own a 1987 740 gle &I'm trying to find the A/C control relay switch which is a little cube with 4 prongs.
The only relays i've found are behind the ashtray - don't know if this is where it's supposed to be or not all of these relays have 6 prongs. I was able to jump from the battery right to the compressor & get it working, it just wont kick on when hooked up normally. Any help would be greatly appreciated.

Thanks
ian

 

i dont know if its the relay, but you might want to check the pressure switches. there is one on the accumulator. you might also have too little pressure in the system. It should read about ambient temperature on both the high and low sides when the engine hasn't been run. the low should read between 20-45 psi with the compressor running.

 

There are two AC relays under the right side of the dash behind the glove box. AC heater/blower motor relay and AC delay relay. The delay relay is the left hand side one.