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!978 With Wiper Electrical Issues

Old 10-13-2018, 01:04 AM
  #1  
dant849
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Default !978 With Wiper Electrical Issues

Hello all....the wipers on my 78 stopped working. I checked the fuse which appeared to be intact (see pic) but I changed it anyway, Worked for a few minutes then stopped again. Checked the fuse again. Again, not obviously blown but check out the other pic. The end of the fuse is taking a bit of abuse as you can see. I unplugged the 2 connections at the motor, cleaned em up good, replaced the same fuse, worked like a charm. Shut her down and cranked up again a few minutes later, no wipers...what is the most efficient way to troubleshoot this? Thanks in advance,
Dan

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Old 10-13-2018, 11:07 AM
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henrikse
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Check the fuses with an ohmeter. Trust you have a multimeter. Sure looks like 2nd pic the fuse melted although at wrong spot. Usually they melt at the narrow spot in window as this is how they are designed. If you put the second one in while wiper motor was on with power you could do this maybe.
Anyway two thinks to check. First these fuse blocks can corrode where you install the fuse at each end. You can clean up each end where the fuse makes contact with a fiberglass pen or steel wool or fine emery. you can use spray contact cleaner. If it is good to start then use a meter on amp scale (30 amp) and see how much your wiper motor is drawing for current?
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Old 10-13-2018, 12:59 PM
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I'd start by cleaning the fuse connectors in the fuse box.... then see what happens. It's common for the terminals in the fuse box to become corroded and when this happens it creates resistance. So clean them.. it's not easy but you can glue sand paper to a small dowel and rub it in and out of the terminal until cleaned.

If this doesn't fix the issue there is a ton of info on my tech page. The link is listed below.

Willcox

https://willcoxcorvette.com/
http://repairs.willcoxcorvette.com/
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Old 10-14-2018, 03:16 AM
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dant849
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Originally Posted by henrikse View Post
Check the fuses with an ohmeter. Trust you have a multimeter. Sure looks like 2nd pic the fuse melted although at wrong spot. Usually they melt at the narrow spot in window as this is how they are designed. If you put the second one in while wiper motor was on with power you could do this maybe.
Anyway two thinks to check. First these fuse blocks can corrode where you install the fuse at each end. You can clean up each end where the fuse makes contact with a fiberglass pen or steel wool or fine emery. you can use spray contact cleaner. If it is good to start then use a meter on amp scale (30 amp) and see how much your wiper motor is drawing for current?
thanks for your reply. I cleaned up the fuse block again and the wipers work so hopefully that was the biggest part of the problem. However, now instead of two speeds I only have one no matter what position I put the wiper switch in...
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Old 10-14-2018, 03:18 AM
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Originally Posted by henrikse View Post
Check the fuses with an ohmeter. Trust you have a multimeter. Sure looks like 2nd pic the fuse melted although at wrong spot. Usually they melt at the narrow spot in window as this is how they are designed. If you put the second one in while wiper motor was on with power you could do this maybe.
Anyway two thinks to check. First these fuse blocks can corrode where you install the fuse at each end. You can clean up each end where the fuse makes contact with a fiberglass pen or steel wool or fine emery. you can use spray contact cleaner. If it is good to start then use a meter on amp scale (30 amp) and see how much your wiper motor is drawing for current?
Originally Posted by Willcox Corvette View Post
I'd start by cleaning the fuse connectors in the fuse box.... then see what happens. It's common for the terminals in the fuse box to become corroded and when this happens it creates resistance. So clean them.. it's not easy but you can glue sand paper to a small dowel and rub it in and out of the terminal until cleaned.

If this doesn't fix the issue there is a ton of info on my tech page. The link is listed below.

Willcox

https://willcoxcorvette.com/
http://repairs.willcoxcorvette.com/
thank you very much.. Lots of good info on your links there. I appreciate it
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Old 10-14-2018, 10:39 AM
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Yes if only one speed use the Willcox website to bench test your wiper motor. These are old and the wiper switch is a terrible switch. Originals can be taken apart and cleaned up but rotten design. It can also be tested out of car. New ones from China intermittent too.
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Old 10-14-2018, 11:01 AM
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Originally Posted by henrikse View Post
Yes if only one speed use the Willcox website to bench test your wiper motor. These are old and the wiper switch is a terrible switch. Originals can be taken apart and cleaned up but rotten design. It can also be tested out of car. New ones from China intermittent too.


The imported switches are hit or miss with about 1 out of 10 being junk.

Here is how to rebuild the switch: http://repairs.willcoxcorvette.com/w...tch-repair.pdf

Here is how to test the switch once you get it out of the car.



If the car is in my shop I'll just rebuild the switch vs, selling a new one. And while it's hard to get the pot open, if you do decide to pull it apart just pay attention to how it came apart and don't drop the spring inside.



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http://repairs.willcoxcorvette.com/

Please bump our sale threads if you get a chance..

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