Author Topic: Windshield Washer retrofit wiring  (Read 9863 times)

Offline paniolo

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Windshield Washer retrofit wiring
« on: October 15, 2011, 01:30:03 pm »
I have the combined washer/wiper assembly in my '81 Suburban.  I put new seals in it and it worked marginally, but I was also missing one of the metal nozzles.  So I got some generic nozzles and mounted them to the cowl vents, but they seem to flow more than the original and fluid meekly spurts out of them.

I had a later model washer reservoir with the electric pump on the side in my spare parts.  My goal is to use this and have the original washer/wiper switch run it so the whole system appears as OEM.  Doing a bench test this set up generates plenty of spray volume through the after market nozzles. 

I probed the two wires to the washer relay coil and hooked the positive to the red lead  and the negative to the other.  When I push the washer switch the washer runs and sprays great, but it runs continuously after I release the dash switch.  Any suggestions on how this should be wired to use the oem switch?
David M.
'81 C20 Suburban, tow pkg, 454, TH400, 14bb

Offline bake74

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Re: Windshield Washer retrofit wiring
« Reply #1 on: October 15, 2011, 05:21:14 pm »
     Did you look in the tech section under wiring diagrams ?  If you did then somebody who has actually torn into that system is the only ones who would know.
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
#2: There is no such thing as impossible, it just takes longer.
  74 k10, 77k10    Tom

Offline paniolo

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Re: Windshield Washer retrofit wiring
« Reply #2 on: October 15, 2011, 07:28:15 pm »
Yeah, I've got the wiring diagram.  I thought the switch was a negative ground, so I hooked up the positive to the constant hot on the washer relay and then the negative to the other side.  But when energized it won't shut off.  So yeah, I'm hoping somebody that has already dug into the relay can point me to a correct wire.
David M.
'81 C20 Suburban, tow pkg, 454, TH400, 14bb

Offline paniolo

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Re: Windshield Washer retrofit wiring-SOLVED
« Reply #3 on: October 27, 2011, 12:19:10 am »
OK I figured it out ... as often happens it was user error.  I thought I had located the washer relay coil, but was actually using the Park Switch.  The park switch is the closest two connector terminal to the washer outlets and the washer coil is a two connector terminal more in the central area. 

It now works as stock.  Push in the original washer switch and as long as it is held in plenty of fluid volume comes out.  When released the wipers finish their cycle and then park.  My stock intermittent wipers and washer now work perfectly.

I took a reservoir from a 85+ with the attached pump.   It bolts into the same location on the fender.  Remove the washer relay coil connector and wire the red from the pump to the pos and the negative to the other side.  When the washer switch is pushed it completes the ground and the pump runs.  Pics of the reservoir and the connector follow.
David M.
'81 C20 Suburban, tow pkg, 454, TH400, 14bb

Offline 1980c10

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Re: Windshield Washer retrofit wiring
« Reply #4 on: October 28, 2011, 02:35:42 pm »
Thanks for posting the fix, too often that doesn't happen.

Offline paniolo

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Re: Windshield Washer retrofit wiring
« Reply #5 on: October 28, 2011, 04:17:58 pm »
Hope to help the next guy! 

Though last night the wipers were working fine in the rain ... but then my son turned on the heater and the wipers stopped.  When he turned the heater off a few min later the wipers worked again.  Gotta believe that is coincidental ... but ??  It's always something else. :D
David M.
'81 C20 Suburban, tow pkg, 454, TH400, 14bb