Windsheild Wiper ON = Engine Shutdown

Discussion in '99+ 7.3L PowerStroke Engine & Drivetrain' started by Unkle_Willy, May 22, 2020.

  1. Unkle_Willy

    Unkle_Willy SDD Junior Member

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    OK this one seems really strange. I just picked up a '99 SD 7.3L. Tested the operation of everything before buying it - all was OK. Including the wipers. Used the wipers once or twice since I got it - still OK. Today, fired it up and hit the wipers - engine immediately shut down. No stumbling or missing - just a total shut down. I restarted and repeated this four or five times, shutdown every time. Rain quit so I drove to where I was going, hit the wipers when I got there after a thirty minute drive - instant shutdown. Drove back home, same thing. So I pulled the wiper fuse (#11) and tried every position of the wiper stalk - no effect, engine kept running. Put the fuse back in and tried the wipers
    - all is fine, engine kept running. So now I have a potentially dangerous problem that could reappear anytime I use the wipers, and no idea what is causing it. Anyone have suggestions?
     
  2. john mathis

    john mathis SDD Junior Member

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    Just a thought.... if you have tilt steering there could be a wire or combination of wires getting pinched causing your issue. Fire it up and move the steering wheel up and down while turning on and off the wipers. At least that's where I'd start. Good luck and let us know what you find.
     
  3. Unkle_Willy

    Unkle_Willy SDD Junior Member

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  4. eZAK61

    eZAK61 Full Access Member

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    Being an electrician for 35yrs. My first thought would be a bad relay.
    I believe there is one that will shut off the wiper motor upon crank.
    Test; >Turn ign. sw. to 'on' >turn on wipers >Start > wipers should stop while motors starts.

    My logic would indicate that by turning on the wipers your telling the ECM to start the engine.

    Also, By pulling the fuse tells me you interrupted the circuit, holding the relay closed.

    *Of course, This is just my thoughts and I could be wrong.

    That being said, I did buy a program for my laptop (smart phone / tablet also) That connects to the OBD, which gives one the ability see all the parameters,
    And make changes if so desired. OR, Leave the fuse out until it rains, then take it to a qualified tech.!
     
  5. bigb56

    bigb56 SDD Junior Member

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    This is a known issue with after market camshaft position sensors (Ford calls it a CMP although some call it a CPS). The frequency that runs the wipers on intermittent mode interferes with the signal from the after market part. Put in a genuine Motorcraft CMP. Its on the front of the motor, accessible from underneath with a 10mm wrench. Also check the pigtail and wiring for any chafing.
     

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