2003 Mercury Marquis A/C compressor engages when heater is

NBMICH78

MEMBER
2003 MERCURY MARQUIS
V8
2WD
AUTOMATIC
52,000 MILES

When I turn on my heat, the a/c compressor/clutch cycles on amd off every 1-2 minutes. I know it should turn on when I use defrost, but it also turns on whenever I use the heat as well and it keeps cycling on and off. Any idea what can be wrong and what I should check?

Monday, October 12th, 2009 AT 8:12 PM

2 Replies

BMRFIXIT

MECHANIC
19,053 POSTS

If you have automatic HVAC system suspect
Automatic temperature control module and its big BIG $$$$$$$

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Monday, October 12th, 2009 AT 8:34 PM

NBMICH78

MEMBER
4 POSTS

Hi, my hvac is not automatic. Its manual.
I dont know if this is related, but I replaced the blower motor resistor and wire harness recently because the fan would only blow when set to high. That solved the issue, but now I noticed the a/c compressor kicks in every time I use the heat. And it keeps cycling on and off every 1-2 minutes. Should I just disconnect the compressor for the winter? I dont want it to fail pre-maturely. Or should I check something else?
Thanks

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Tuesday, October 13th, 2009 AT 9:30 AM