P0645 – Air conditioning (AC)
By (Contact Me)
Last Updated 2015-11-18
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| Trouble Code | Fault Location | Probable Cause |
|---|---|---|
| P0645 | Air conditioning (AC) | Wiring, AC system |
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"Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth." - Sherlock Holmes
Liguei meu Ar Condicionado direto sem o módulo ( Fiesta 2009/2010 ), pois o relé estava mandando pouca corrente negativa e não gelava, passei 2 dias tudo ok, o Ar ótimo, agora parou de novo de gelar e apareceu o cód P0645, possível causa fiação. Oque fazer? Grato desde já.
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Do I have a relay for the AC clutch and the front and in the back trunk fuse box if so what number please
The AC clutch relay should be under the hood in the Integrated Power Module, AKA “Fuse Box,” right next to the horn relay. I read the Horn Relay and AC Clutch Relay are fed by the same fuse, so if the fuse blows, you lose Horn and AC. Also, the horn relay and AC relay are identical, so you should be able to swap-tronic them.
I change all of them .. Still same.. If it hook meter up to plug that goes in to the ac clutch i get 10.7v dc and when i hit ac button in car it goes to 11.5.v Dc If in unplug it from ac clutch and i wire my own 12.v dc it comes on and cold and i check freon presser when ac clutch is engaged and it read normal on ac presser Freon.. Iam confused .. Is 11.5v not enough to kick it on. Please help.. Lol
This might be getting too complicated to diagnose over the internet, but I’m wondering if you might have a bad ground after the AC clutch. If you’re getting 11.5 V, it seems like 2 V are getting sucked up somewhere else. Double-check you have ≈13.5 V engine running AC clutch disconnected AC engaged, then check ground straps and other ground points for excessive resistance.
Took it to have it service.. they ran scan on it come to find out it is the pcm.. I ran a switch to the ac clutch so I manually turn it on until my com comes in.. thanks for your comments