2004 AC compressor clutch not getting elec power
 

I have a 2004 Expedition and the AC clutch is not getting electrical power.
I have checked all fuses tied with the AC system and all look good and have continuity. The low and high pressure switches have continuity as they are installed in the system (engine not running) and the connectors going to the pressure switches have 12v supplied to them.
I bypassed the electrical system and powered the AC compressor directly from the battery to confirm the clutch worked normal. I then started the engine and applied electrical power to the AC comp and checked the pressure on the low side only (cheap service fill gage) which is showed aprox 42 PSI. The air in the car did get cooler also.

What could be stopping the power from getting to the AC comp? Any ideas to check? I guess I should get a repair manual to get the elec schematic of the AC system for trouble shooting.

Thanks

There may be an A/C clutch relay not working. If you have the owner's manual look in the electrical section for the relay locations and it should direct you to the relay to check.

The only reference in the owners manual is 3 fuses for the AC system. #11 is for the compressor. All 3 have beeen checked OK and also swapped.

Any other ideas?

Thanks

There should be a page that has a picture of the relays and their position and system they control.

AC clutch relay is out in the 'auxiliary relay box 1'.

Left (driver side) inner fender area forward towards the radiator support..

I have that from the owners manual. Fuse #11, #13 and #18 are the only ones dealing with the AC system and #11 is for the AC compressor. Nothing is mentioned to it going to a relay.


I have looked and havent located it. Even had a parts store personnal look and he didnt find it. I will re-check.

Thanks for your help.

GREAT NEWS!!!

Thanks a million hanky and Hayapower. The AC s now working.
I did locate the aux relay box 1 exactly where you said it was. I removed and checked the diode and the relay with the relay failing intermittently. I swapped it with one from the main relay/fuse panel and the AC still didn't work. I then went back to the compressor wiring connector and noted it was a bit dirty. After cleaning it the AC system now works normal.

Your help is greatly appreciated...

Glad it was a simple fix..

Thanks for the update. Always nice to know the problem is solved.