1997 Ford Thunderbird AC operation

Tiny
SCALEYDINO
  • MEMBER
  • 1997 FORD THUNDERBIRD
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
Ok here we go. I've done everything to this ac unit but can't get it to work, it's not low on freon, pressures are fine low pressure and high press, cut off are fine. Clutch coil, compressor, are fine ac heat switch in car is fine. I checked everything, jump wrong the low pressure switch didn't work. Pulling PCM didn't work have power going into PCM good, ccrm blk/ yl has power coming from ccrm but it stops about a foot away have complete continuity through circuits. I have b+ at ccrm, PCM, low pressure switch high pressure switch, but nothing in wire going to compressor. I can jump compressor and it works fine. The damper doors seem to work although I have tested used and new switches. I'm going crazy. Nothing makes sense. All fuses are good I can hear the ccrm contacts working. Is there a relay somewhere. Power panel in engine doesn't have one for ac just a horn relay it seems to be. Is it somewhere else. Again have inputs where they need to be but the blk/ yl Eire coming from ccrm has power but only for a short distance. Help me please
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Saturday, May 31st, 2014 AT 1:04 PM

3 Replies

Tiny
FREEMBA
  • EXPERT
Check the blk/ yl Eire coming from ccrm where the power stops (disappears). The wire may be broken there. Flex the wire by hand to "feel for a break.
Or, with the battery disconnected, use an ohmmeter to check continuity in that area of the wire. Push a straight pin through the insulation of the wire at the last point where you had power. Push another one through the insulation about a foot away from that point. Connect the ohmmeter to the pins. If there is a break there will be no reading on the ohmmeter. Wiggle the wire during the test (because there could be a bare part of the wire touching the body of the vehicle.)
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Sunday, June 1st, 2014 AT 7:16 AM
Tiny
SCALEYDINO
  • MEMBER
Thanks for the reply. I stated in my post I had continuity through out that circuit. But the power blk/YL Fromm ccrm has power for about a foot then it disappears. I can still have a break in wire? Even when continuity checks out for the whole distance of that wire. You say it could be grounded? I read that if the high pressure cut off has power then the ccrm relay is bad is this true? I have correct voltage inside heat ac controller, 12V at low and high but power only for a foot on blk/YL.? Still look for a bad wire?
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Sunday, June 1st, 2014 AT 8:11 AM
Tiny
SCALEYDINO
  • MEMBER
I figured out the issues. There were 2 blk/ YL wires coming from ccrm. It was the other one. Had a bad ccrm replaced and clutch is cycling. But not correct. Going to pull a vacuum and re do hopefully this will help. Thanks
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Sunday, June 1st, 2014 AT 10:01 AM

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