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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 47712
Experience:  16 years experience
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Hamman, I have a 2008 Ford Crown Victoria P.I that has an

Customer Question

Hello Dr Hamman,
I have a 2008 Ford Crown Victoria P.I
that has an A/C clutch intirmentant issues running after warm, rpms will fluxuate and sometimes stall. The relays get very hot and the compressor clutch, coil and bearings are good. I have replaced the relays but suspect a diode or pcm issue. Have you had simular problems in the past?
Submitted: 11 months ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 11 months ago.

Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.

So once the vehicle is at operating temp the AC intermittently works. Does this intermittent issue only occur in park or at idle in the drive light at a read light? Do you get the intermittent AC issues when driving?

Customer: replied 11 months ago.
both but the relays being so hot is what's bothering me could it be the diode for the compressor clutch not restricing back voltage or a ground I'm missing.
Customer: replied 11 months ago.
Also while driving
Expert:  Chris (aka- Moose) replied 11 months ago.

Active relays that turn on and off often or those staying on will get very hot.

Are you able to get it hot, and do some electrical testing at that time when the AC is commanded on but not working?

Customer: replied 11 months ago.
It happens to quickly to verify voltage but the rpms at a stop fluxuate and some times stall. Clutch engages and runs smoothly but cuts out rapidly and frequently after engine warms. Replaced relays but not the diode. Also suspect the pcm module but happens to rapidly to test.
Customer: replied 11 months ago.
Relays are Very hot blower seems the hottest.
Expert:  Chris (aka- Moose) replied 11 months ago.

Will the vehicle stall when not using the AC?

Do you own a AC pressure gauge set to monitor the AC pressures?

Customer: replied 11 months ago.
No runs great without ac and yes I'm a HVAC/R tech by trade
Customer: replied 11 months ago.
I did have a problem with stalling before but cleaned the egr and mass air flow then had the stereo upgraded and a few months later started having this issue.
Customer: replied 11 months ago.
Fly by wire is is a bummer to troubleshoot
Expert:  Chris (aka- Moose) replied 11 months ago.

In park, at operating temp, with the rpms held at 1500. AC on max, blower speed on 2.

Tell me the max and min low and high side pressures as the gauges move up and down with the compressor turning on and off.

During this test tell me the outside air temp and the dash output vent temp.

One possible cause for stalling at idle on this model is a dirty sticking throttle plate. Can you try cleaning it with a tooth brush and brake cleaner.

This is my 1st answer, but does not have to be my only answer. You the website and myself expect you to have a great experience with my help. Please let me know if you are pleased by selecting a star rating above or by replying and saying your pleased. Not rating or rating 1-2 stars does not benefit you nor me in any way. Follow up and reply as often and when needed, there is no extra charge to do so.

Thanks Moose.

Customer: replied 11 months ago.
Ok will do thanks
Expert:  Chris (aka- Moose) replied 11 months ago.


Expert:  Chris (aka- Moose) replied 11 months ago.

Hello again Chris here,

  • I am following up with you to see if you got everything you needed from my answer. We're you pleased with my help?
  • If you were not pleased with my help, please let me know by replying so I can help more.
  • This post is coming up on the 7 day mark where it times out. When a post times out, that means it's no longer on my active list (you reply and I may never know it.)

Thanks Chris

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