Close



Results 1 to 8 of 8
  1. #1
    FEP Power Member dagenham's Avatar
    Join Date
    Jul 2016
    Location
    Duncannon PA
    Posts
    1,047

    Default 1985 5.0 4BBL a/c question

    I put a jumper wire on the plug for the full throttle cut out switch but my ac wont kick on. Using a test light revealed no power at the ac clutch. So, which wire on the pressure switch at the firewall is the hot wire so I can see if I have power there? I can guess the pink wire but I'm not sure.
    At the same time though I dont know if there is any or enough freon in the system. A previous owner apparently converted or planned to convert to R134 because the fittings are there. Is there a fuse or relay just for ac that I should check?

  2. #2
    FEP Power Member dagenham's Avatar
    Join Date
    Jul 2016
    Location
    Duncannon PA
    Posts
    1,047

    Default

    Bueller, Bueller??

  3. #3

    Default

    The pink wire is the hot. You can jump the pressure cycle switch to check if compressor runs.
    84 LX Vert. 5.0 5speed canyon red on white
    99 cobra, electric green on medium parchment, vortech s-trim

  4. #4
    FEP Member
    Join Date
    Oct 2017
    Location
    south-central WY
    Posts
    251

    Default

    If you don't already have one, you ought to grab a volt-ohm meter at Harbor Freight, less than $10. Then at the least, buy a refill kit with a pressure gauge and a can of r134a. Follow the directions in the kit up to the point of piercing the can, but don't pierce it yet. This will let you read low-side pressure with the compressor off. This pressure should drop when you cycle the compressor -- the instructions will guide you as to what pressure you should see and when.

    Of course, a full gauge set is more useful, but costs more.

  5. #5
    FEP Super Member
    Join Date
    May 2003
    Location
    Roseburg Oregon
    Posts
    3,308

    Default

    Harbor freight gauge kit is around 50 dollars .
    Has very good instruction sheet .
    clowns to the left of me , Jokers to the right

  6. #6
    FEP Member Mgino757's Avatar
    Join Date
    Jan 2011
    Location
    Virginia Beach, VA
    Posts
    489

    Default

    There is a fuse for the ac clutch. Like others suggested, try jumping the pressure switch connector, that'll let you know if everything else is electrically fine. If the compressor engages, then either the system is not filled or the pressure switch is defective.
    1985 Mustang GT conv. modified 4180C, Weiand Street Warrior intake, equal length headers, true dual exhaust, 3.55:1 8.8'' rear end, 2003 V6 T5, Ford Racing 10.5" clutch.

    1998 Mustang GT auto. PI swapped. Daily beater

  7. #7
    FEP Member SECESH's Avatar
    Join Date
    Sep 2010
    Location
    Catlett's Station VA
    Posts
    161

    Default

    I've been sorting this circuit out. Under the dash, above the clutch pedal, there is (or should be) a relay. I think about five wires run to it. One should be the pink/ blue one from the pressure switch, another will be black with yellow spots and goes out to the clutch. Near as I can tell the switch at the carb just controls this relay. Jump the two wires mentioned above and the clutch should be energized if all else is right.

  8. #8
    FEP Power Member dagenham's Avatar
    Join Date
    Jul 2016
    Location
    Duncannon PA
    Posts
    1,047

    Default

    Thanks guys. I'm gonna have to make some time up so I can check any and all of these things out mentioned above.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •