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Delay wipers

Discussion in 'Electrical & Audio' started by Rob P, Dec 3, 2019.

  1. Rob P

    Rob P Junior Member

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    I'm adding delay wipers and I think I'm having the same problem I had when I undertook this endeavour with a 78 Corvette. The truck is a 78 GMC and never had delay wipers. I added the switch and the delay box but still no fun. Everything works but the delay. I read in the 78 shop manual that a wire plugged in to the ACC port in the fuse box. Can someone tell me what color wire does this splice to? I'm assuming this feeds power to the delay mechanism. On the 'vette, I had the same issue until I figured out I needed a special wiper motor cover and needed to splice a wire coming from this cover into a green wire.
     
  2. Snoots

    Snoots Supporting Member Supporting Member

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    Try this
     

    Attached Files:

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  3. bucket

    bucket Super Moderator Staff Member

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    For '78-'83 trucks, it's just a matter of plugging in the delay box and wiper switch to the existing pigtail in the dash. Sounds like a bum switch or box.
     
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  4. Rob P

    Rob P Junior Member

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    Tried three new switches and three boxes. Nope, the manual for 78 clearly states that a lead goes to acc port in fuse box. 78 appears to have been a disaster for gm wiring
     
  5. Snoots

    Snoots Supporting Member Supporting Member

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    Just find a port that only has 12vdc when the ignition switch is on.
     
  6. bucket

    bucket Super Moderator Staff Member

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    Ok, what lead? There's no extra wire to plug in anywhere else, even if you did know where to plug it in.

    Imho, '77 was the bastard year for wiring. It was a one-year-only delay wiper switch and delay box.
     
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  7. gmachinz

    gmachinz Harnessworx Inc

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    I have to agree that ‘77 was the only goofy year for them. I have refurbished a few of the delay modules and on a couple I suspect a bad IC chip so....I am waiting on my Motorola replacements to arrive so I can solder them in and re-test. These modules can be a little pita at times lol
     
  8. TubeTruck

    TubeTruck Full Access Member

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    Gonna hijack this real quick. Does anyone know where to get good delay boxes? Rockauto sells the switches and they did have the delay boxes at one time recently but I can't find then anymore, and I hear AC Delco stopped making them. I really don't want to get one of those Chinese ones.
     
  9. Rob P

    Rob P Junior Member

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    Well we tried three boxes now, the last coming out or a truck where they were working when removed. I had an electronics guy check one of the boxes I tried and he could find nothing wrong with it. A manual for 78 very specifically says a lead plugs into the acc port on the fuse box. I have no trouble splicing in a wire, I just need to know which color to splice in to.
     
  10. TubeTruck

    TubeTruck Full Access Member

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  11. TubeTruck

    TubeTruck Full Access Member

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    Just found this. Hope it helps

    0900c152800827de.gif
     
  12. Rob P

    Rob P Junior Member

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    What color wire gets the

    Looks like the pink wire gets spliced in to and then into the red wire to the box, which will feed power to the delay circuit. We have a winner! thanks!
     
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  13. bucket

    bucket Super Moderator Staff Member

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    The pink wire is on the ground side of the washer motor.
     

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