Air Cond No Work And Here's What I Found...

Discussion in 'Fox 5.0 Mustang Tech' started by Butterfinger, Sep 30, 2012.

  1. What does this mean? Never seen the rubber chewed up like this before.

    Attached Files:

  2. :ot: WRONG FORUM SIR.
  3. AC clutch failure ???
  4. Like the man said, wrong Forum - you need to put this in 5.0 Tech. Until that happens, here's some help...

    The clutch hub separated from the plate because the rubber that connects them sheared off.

    The A/C clutch is about $100 new or you can buy a compressor from the junkyard with a working clutch for about $50. The puller is about $16 if you have to buy one, Autozone will rent you one for free.

    The clutch hub is usually what fails, the rubber shock damper shears off from the steel hub and plate. The pulley turns, but the hub doesn't when you power up the A/C.
    [​IMG] Ford MOTORCRAFT Part # YB289A $39.00

    The hub comes off without much problem if you have the puller. You don’t have to do anything with the refrigerant (R12 or R134a), you can replace the clutch without draining and refilling the system. The snap ring hiding inside the hub is the only tricky part.

    Remove the nut; remove the snap ring (if present) and then remove the washer. Loosen the puller tool center bolt so that you can get the larger threaded section of the puller screwed into the clutch hub. Tighten up the center bolt on the puller and the clutch hub will come off.

    Clutch hub puller tool

    AutoZone and most other major auto parts chain stores will rent or loan the puller

    Some electrical checks to do if it doesn't work after you replace the clutch hub...
    A few simple electrical tests are advised before popping out the wallet to buy a clutch assembly. With the engine running, use a test light connected to the 2 wires on the A/C clutch harness to make sure you have voltage when you turn the A/C on. If the system is low on refrigerant, the clutch will not engage (safety feature, keeps you from burning up the compressor due to no oil). There is an aluminum canister on the firewall with a large hose leading to the A/C compressor. There is a pressure switch on it with a 2 wire connector: pull the connector off and jumper the wires. The compressor circuit will power up, and the test light will light if the electrical circuit is good. This test is also a good way to check the compressor & clutch if the system is low on refrigerant. You can jumper the wires and the compressor will turn if the clutch is good.

    The clutch also has a relay that shuts off when you go to WOT (wide open throttle). It is located on the passenger side inner fender well. The close proximity of the relay to the headers can cause the insulation on the wiring and the relay socket to deteriorate. The relay can become non functional when this happens.

    Diagram courtesy of Tmoss & Stang&2birds

    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Everyone should bookmark this site.

    Ignition switch wiring

    Fuel, alternator, A/C and ignition wiring

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs

    Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs

    Vacuum diagram 89-93 Mustangs

    HVAC vacuum diagram

    TFI module differences & pinout

    Fuse box layout
  5. Thanks jrichker...very helpful.

    Opps...I posted this in the incorrect spot. This site upgraded, I thought I was putting it in tech, I should've scrolled down first.

    I've become "that guy"...D'OH!
    gearheadboy likes this.
  6. Awesome tech post jricher
  7. It's all good!