1995 Grand Marquis- A/C compressor quit engaging. System charged properly, all fuses/relays OK, all grounds good, no voltage to comp.

Asked by Dec 16, 2015 at 01:19 PM about the 1995 Mercury Grand Marquis 4 Dr LS Sedan

Question type: Maintenance & Repair

A/C compressor inop. All fuses/relays OK, system charged properly, all
grounds good, no obvious damage, air gap@ comp. clutch- .002. Display on
control unit inop., all other functions operable

7 Answers

19,715

are the high/low pressure switch ok...

1 out of 1 people think this is helpful.

Jumpered the sw, no change.

6,215

manual or automatic controlls?

1 out of 1 people think this is helpful.
6,215

Also analog or digital cluster?

1 out of 1 people think this is helpful.

Analog cluster, auto. controls

6,215

Ok, so Im going to assume some things since you said that the fuses and grounds are good but some of it will be back tracking. Power flows from the cluster to the red wire pin 20 @ the eatc head, then out pin 25 purple wire to low cycling switch, then out on pink light blue wire to the high pressure switch, and on to the ac cutout relay. after the a/c cutout it has a split, one to the compressor clutch the other to the a/c diode. All of this is 12v if you have power by your volt meter or test light at the low side switch then the controll head should be somewhat functional. if there is power jump the switch and check at the high switch, if power there jump that and check power @ the cutout relay, this is where the pcm comes in by providing a signal to close the relay under normal conditions. the pcm will open the relay if it sees wide open throttle or and overheat condition. you can jump past the relay to check for power to the compressor and a/c diode. if the diode is bad it will pull power from the compressor and not allow it to work.

1 out of 1 people think this is helpful.

Thanks, Guy. I'll try all that, but It'll probably be tomorrow before I can get to it. Have some other (unrelated) fires that hafta take priority. (The fun just never stops)!! I'll post as soon as I've gone thru the steps you outlined. Thanks again!!

Your Answer

Add photo

Related Questions

  • A/C Leaks Problem HELP HELP HELP. 4 answers

    I have had my air serviced this past weekend 6/21/2014 and while refilling the aire they said that they did not see any leaks and so i paid and left. Well well well five mins later as im going to eat ...

    2005 Mercury Grand Marquis LS Ultimate

    -

    Maintenance & Repair

  • All Vents work and air comp works but air will not come thru any vent- 1 answer

    Air from outside and air from compressor wont come thru any vents. Heat does come thru any vent.

    1999 Mercury Grand Marquis 4 Dr LS Sedan

    -

    General

  • Head, Brake, Signal, Reverse/Back-up lights work, but Tail, Park and Panel lights don't 9 answers

    I jumped the battery a while back. i don't know if this caused the problem. But, afterward, I started having problems. The headlights work. Brake lights work. Turn signal lights work. But, the t...

    1997 Mercury Sable 4 Dr GS Sedan

    -

    Maintenance & Repair

  • my Cougar has no heat 1 answer

    I have a 1999 Mercury Cougar with the 2.5 v6. It has no heat. The air conditioning works perfectly. it doesnt over heat, Ive replaced the thermostat, upper radiator hose, lower heater hose and done a...

    1999 Mercury Cougar 2 Dr V6 Hatchback

    -

    Maintenance & Repair

  • MERCURY MONTEGO 2006 - RESET COMP. AFTER OIL CHANGE. PROBLEM! 6 answers

    I changed the oil myself today and this time I found a problem when trying to erase the typical message "OIL LIFE 0%" or similar. When handling SET UP, RESET & INFO thru the small keys beside the wh...

    2006 Mercury Montego Luxury

    -

    Maintenance & Repair

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 2,148 nationwide Grand Marquis listings starting at $1,985.

ZIP:

Search Mercury Grand Marquis Questions

UK Questions

Are you a UK consumer? CarGurus now has a discussion forum in the UK.

Mercury Grand Marquis Experts

#1 Tracy Hooks
Tracy Hooks
Reputation 5,030
#2 kbro
kbro
Reputation 2,020
#3 Js08016
Js08016
Reputation 1,580
View All

Related Models For Sale

Used Ford Crown Victoria
4 Great Deals out of 1,394 listings starting at $1,700
Used Lincoln Town Car
36 Great Deals out of 2,144 listings starting at $1,995
Used Chevrolet Impala
891 Great Deals out of 35,196 listings starting at $1,700
Used Ford F-150
3,031 Great Deals out of 207,234 listings starting at $1,990
Used Cadillac DeVille
4 Great Deals out of 1,954 listings starting at $1,600
Used Chevrolet Tahoe
859 Great Deals out of 27,932 listings starting at $1,700
Used Honda Accord
992 Great Deals out of 74,858 listings starting at $899
Used Buick LeSabre
13 Great Deals out of 2,251 listings starting at $1,299
Used Toyota Camry
1,183 Great Deals out of 95,109 listings starting at $1,250
Used Ford Taurus
302 Great Deals out of 21,176 listings starting at $1,500
Used Chevrolet Camaro
437 Great Deals out of 40,503 listings starting at $3,500

Used Cars For Sale

2011 Mercury Grand Marquis For Sale
45 listings starting at $7,500
2010 Mercury Grand Marquis For Sale
6 Great Deals out of 120 listings starting at $2,999
2009 Mercury Grand Marquis For Sale
4 Great Deals out of 105 listings starting at $2,995
2008 Mercury Grand Marquis For Sale
4 Great Deals out of 155 listings starting at $2,995
2007 Mercury Grand Marquis For Sale
8 Great Deals out of 163 listings starting at $1,985