Mechanic help needed

Discussion in 'Trucks and Trailers' started by Lech615, Jun 12, 2002.

  1. Lech615

    Lech615 LawnSite Member
    Messages: 105

    I have an 86 F150 with a 302. I think there is a short somewhere in the lectrical system. My a/c & heat used to work fine, now it sometimes works and sometimes does not. When I switch the a/c on you can hear the veents open, but the blower motor doe snot come on. Where or how would I go about checking the system to find the problem? I am desperate here because it effects the way the truck drives sometimes, please help.


    Carl:confused: :confused: :confused: :( :(
  2. Alan

    Alan Member
    Messages: 1,185

    We've got a similar problem with our 97 Chevy. Problem on that one seem to be inside the motor. If you slap it upside the head it comes to life. We've got a spare motor on the shelf for the day this one refuses to wake up. Seems like you could check for voltage at the motor connector pretty easy, that would tell if you've switch/wiring problems or a bad motor.
  3. Pelican

    Pelican LawnSite Member
    Messages: 164

    You'll have to start tracing circuits as Alan suggested, your problem could be in a number of places. Check for power at the switch, then out at the blower.

    The switch contacts could be dirty as could the wire connectors. There's a rheostat inside the blower housing that controls blower speed, check your connections here. They are exposed to dirt and moisture under the hood and are the most likely to corrode. I've also seen the rheostat rust out from exposure to moisture. Good luck
  4. scott's turf

    scott's turf LawnSite Senior Member
    from NH
    Messages: 949

    Unplug the blower unit and run it directly to the battery to see if it runs. If not take out the 4 bolts and go to the junk yard and pick one up. I did that for my f250 last year and it only cost me $10 and it has been working for over a year. It only took about 5 mins of total time to fix.
  5. Brickman

    Brickman LawnSite Bronze Member
    Messages: 1,249

    Some blowers are so easy to change it is silly. A ten year old could do it. Others require a stick of dynamite to change. :D

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