68 Riv; Wiper Motor Woes

Discussion in 'Sparky's corner' started by Briz, Nov 14, 2018.

  1. Briz

    Briz Platinum Level Contributor

    Was at the Nationals with the Riv. Friday morning it was pouring rain as I entered the car show area. Was directed to my spot. Flipped off the wipers and they stopped straight up and down never to move again no matter what I've done. I do have power going to the motor. Fuses are good. Acc Relay is good. everything else in the car works. Have 2 other like motors in the shop. neither one show any life when connected to the car wiring or a ext battery. Purchased a new reman motor from the local parts house. Plugged it in and it made one revolution and stopped. Have not been able to duplicate again. Looking at the wiring diagram in the back of my chassis manual and it seems the power for that motor is routed through the horn relay on the left inner fender. Horn works so Id guess the relay is good. At a loss as where to turn next. I have a extra switch from the parts car. Will try that next. Ideas?
     
  2. buick64203

    buick64203 Right wing conservative Staff Member

    If you go on youtube, there are videos on exactly how to bench test a wiper motor. I would get the wiper motor to work on the bench first.
     
  3. pbr400

    pbr400 68GS400

    Washer pump connected? If it fails but is still connected the wiper motor won’t work.
    Patrick
     
  4. Daves69

    Daves69 Too many cars too work on

    Briz the switch applies ground to the motor depending on the speed. Also make sure the motor is properly grounded.
     
  5. Briz

    Briz Platinum Level Contributor

    Great Idea. I should have thought of that on my own!
     
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Check the wiper switch ground as well, that’s a common problem in the A bodies. Ground gets disconnected at the switch mounting. Wipers do all kinds of crazy things.
     
  7. Briz

    Briz Platinum Level Contributor

    Youtube vid was informative. I'll do the bench test next time Im out there. Would have never guessed that the motor was neg switched
     
  8. gstewart

    gstewart Well-Known Member

    That was the solution to the problem, that happened on the day I purchased my GS, where the wipers would continue to function even after the switch was turned off.
     
  9. Briz

    Briz Platinum Level Contributor

    I did the bench test to the new motor and it worked. Tried it on the motor still in the car and it did not. Also tried it on another old one I had on the shelf. No Go. Later I'll pull the old off the car and try again.If not will install the new one in its place.
     
  10. Briz

    Briz Platinum Level Contributor

    Installed the new motor on the car. hit the switch and it went back and forth about 5 times. shut it off and turned it back on and nothing. Went back to the bench test, nothing. Took that and my core to O Really's, ordered another. While there I'm looking at the guts of the old one and I see the parking tang stuck against the gear that turns the washer pump. Used my pocket knife to get it to set back in its place. When I get back home just for grins did the bench test again and it works. WTH? Next time Im out there will clean all the old grease out of it and put in some fresh. test it again several times then reinstall and see what happens.
     
  11. Briz

    Briz Platinum Level Contributor

    Where it stands now is that there is an intermittent problem in the wiring. After messing with this for days I've come to an understanding that the wiper motor has full time power to the center terminal anytime the key is on. The switch makes and breaks ground. I'm losing power to the motor. It comes back, works for a few mins and I lose it again. Supply power directly to the center connection and it works like a charm. Been several times its stopped. Put power to the center wire for just a second and it works on its own again for a few mins then stops. If I let it set for an hour it will work then quit. Its almost like there is a weak breaker or overload switch somewhere in the system. Looking at the wiring diagram I dont see anything like that. Im about ready to just run a fused /switched hot wire into the motor and call it fixed.

    KIMG0278.JPG
     
  12. Daves69

    Daves69 Too many cars too work on

    Briz,

    Try moving the wires at the bulkhead connector or take the connector apart and that put it back together. There may be a dirty connection.
     
  13. buick64203

    buick64203 Right wing conservative Staff Member

    So your saying the yellow wire is the issue? Looking at the schematic, the yellow wire gets power directly from the wiper fuse. When it loses power, do you still have power at the wiper fuse? Dave may be onto something.
     
  14. Briz

    Briz Platinum Level Contributor

    Yes. constant power at the fuse. Yellow wire carries power to the motor as well as the washer pump solenoid. Gonna be a real pain getting down to the bulk head connector. Will be my next move. Thanks.
     
  15. telriv

    telriv Well-Known Member

    What I've found in the past is the ground at the wiper switch. EVERY GM car has a diff. way to ground the switch & when put back together this small detail is normally missed. Just went through this on a '69 GTO. Next is the bulk head connector. I had one on a '71 Riv. one time that the electric downshift would NOT work. Had power at the switch at the gas pedal but NO power at the switch at the trans. Although it had power in & out when the gas pedal was floored. Turned out from the factory the wire in the bulk head connector was NEVER making contact. The customer stated it did work at one time, which I doubt. Ran new wire through the bulk head connector & NOW EVERYTHING was good.
     
  16. Briz

    Briz Platinum Level Contributor

    I thought about that and from the schematic it looks like the wiper switch shares its ground with the headlight switch. I did use my test light to make sure that switched ground was being applied when the wiper was turned on. Last time I had the bulkhead connector apart the hood was off and it was still a pain to access then. Will try to reach down in there and wiggle stuff around to see if I get any life out of it when switched on. I may just go with plan A and try to hide my handy work.
     
  17. kack

    kack Well-Known Member

    Inside the Wiper Motor it is a Circuit breaker.
    Need som cleaning sometimes. Goran
     
    Briz likes this.
  18. kack

    kack Well-Known Member

    If the Wiper linkage is sluggish, the loading on the Motor will be to much.
    And the Circuit Breaker will open. Goran
     
  19. Briz

    Briz Platinum Level Contributor

    Thank you for the suggestion. At first I thought that was in fact the problem but later verified that power was dropping out of the circuit. I'll get a chance later today to go out and mess with it.
     
  20. kack

    kack Well-Known Member

    Happy if i can help. Goran
     

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