air suspension pressure switch wiring

Hello - I had some issues with either my relay, or pressure switch, that caused my compressor to not get power. Ive tested the compressor separately and it works. Not sure how the previous owner had it wired, as i cant access the trunk (previous owner put in a custom box that i cant remove). I do know that the purple wire was connected to ground. The red wire was not used. The blue wire was being used. Can someone please tell me how the blue wire should be connected to the relay, so that it kills power to my compressor when psi has been reached??

Have you actually tested that switch?Gary Sather

I was trying to, to see if i need a new one. But wanted to make sure i had it wired correctly before determining it was bad. How likely is it for a relay to go bad, vs. the switch going bad?

Depends on the wiring. If the switch controls the relay coil, unlikely for the switch to fail. If the switch is in series with the compressor at all, then possible for the switch to fail. Is the relay protected from the elements, not exposed? Did you google the switch part number to obtain the specs/ wiring? Mark

NORMALLY CLOSED     BLUE      RED      COMMON      PURPLE NORMALLY OPEN Gary Sather

The switch was next to the compressor under the car, I believe the relay is somewhere in the trunk that i cant get too. I did get the documents for the switch, but doesnt make much sense to me. Not familiar with the closed, normally closed. I do know he had clipped the red wire. Was using the blue wire, which i believe was providing negative current to the relay? I tried a few things, which i will post separately below

I tried hooking it up similar to this diagram. Except the switch is not hooked to ignition. The blue wire from the switch is going to 85. My relays have both 87 and 87a, which i hook up to Battery.the compressor runs, but doesnt turn off. Whats the correct way to attempt this using the switch i have?

Last post, 87a NOT used. Then the compressor will turn off.

howie ll wrote: Last post, 87a NOT used. Then the compressor will turn off.

Just tried this and get no power. Power only comes on if connected to 87a. So i guess this confirms the switch is bad, ill look around for a nee one. Thanks everyone