My mechanic told me to replace the AC high pressure switch but for $72 I want to make sure it is bad. It is a 3 pole switch on a 2002 ford windstar 3.8 v-6. Can I test it with a simple voltage/ohms tester? My mechanic said the compressor would run only if he jumped the wires on the switch plug so I would assume the switch should have continuity on at least two poles. That does not seem to be the case though.

 

If he can get the compressor to kick on my jumpering the switch, that's pretty much the problem.

 

Did he put a manifold guage set on your system and check the pressures?

 

You can't get a guage reading accurately if the compressor does not come on.

 

Yes he used a manfiold gage set with the compressor running and the pressure was within normal range. What I was looking for was how to test the switch with an ohm meter. I tried a switch from an older Ford and it did not work but the older models have a different control module. I suppose the fact that it did not work makes me cautious about buying a new switch with no refund possible.

 

I went through a similar incident with my wifes car. I tried troubleshooting the best I could and couldn't get it figured out.

I could get the compressor to come on by jumpering the relay so I knew it wasn't that.

The dealer replaced the pressure switch with no change. Then they replaced a thermostatic switch in the air box, no change.

It turned out to be a bad control panel. I had two control panels on hand, turns out both were bad. I never knew if that was the true cause or not because when I told them I thought it was the harness because I could get the compressor to come on by moving the wiring harness going into the panel. Oh well. Good luck!