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Discussion Starter · #1 ·
I set my chevelle resto aside for awhile to tend to a wiper problem on my 70 vette. Hideaway wipers, similar to 70 chevelle I'm told. The wipers came on and swept the window, but when I turned the dash switch off, they stopped dead on the window and refuse to park. Now I can't get them to start up and park. I searched this site and got good info from Elltree and Bob M. However, I still haven't tracked down the problem. I suspect the relay assembly which is the plastic switch device inside the wiper gearbox. Anyone have this same problem and it turned out to be that? Does anyone know where I can buy a new relay assembly that goes in the gear box. May have to try process of elimination. Dash switch seemed to check out okay.
I posed this problem on a corvette site and got no real help, other than a good wiring diagram. This site is the best for anything GM.
 

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I also am in the hunt for that old style park switch assembly. The original part number is discontinued but my parts guy has something on order that we're hoping is the same as the old one. The old switch has the terminals for the wiring harness outside of the washer pump body while the service replacement switch has the terminals through an opening in the washer pump body. I bought four new GM wiper motors a couple years back because the price was right, then I couldn't find old style washer pumps. Ground Up sells washer pumps but they won't fit my wiper motors unless I can change the doggone park switches. GRRRR! I should know something by Wednesday..

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Discussion Starter · #3 ·
tell me how it goes with that relay assembly switch mechanism. I took my wiper motor with gearbox out of the car this am. The motor runs when I put power to the black wire with pink stripe coming out of the motor, and of course when I ground the case. So it looks like the motor is fine. When I test continuity across the switch terminals, the red one on one side, and the black with pink stripe on the other, I don't get any current passing from red to black w pink wire. So it must be the switch assembly in the gearbox. Issue now is where to get one.
 

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We hit the wall today, GM apparently no longer makes this part or we haven't found a part number that will work yet. I'm calling a place in New York
http://www.wiperman.com/ , hopefully they will come through for us.

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Never be afraid to try something new.
An amatuer built the Ark,
Professionals built the Titanic.
Team Chevelle Gold #33
ACES Member #02913
 

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Your problem may be the wiper motor ground. On you Vette the wiper motor is grounded by a black wire that is routed to the blower motor (grounds the blower motor) and then to the starter where the wire is grounded. Without the ground the wipers will not park.
 

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The New York connection was a bust, our cars are too new for this place. Still looking though.

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Never be afraid to try something new.
An amatuer built the Ark,
Professionals built the Titanic.
Team Chevelle Gold #33
ACES Member #02913
 

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Discussion Starter · #7 ·
I just came from the garage. I fixed the relay switch assembly myself. I will now describe my symptoms, diagnosis and repair for all to benefit from.
SYMPTOM--- wipers would come on sometimes, not always. In the end, they come on, but when I turned off the switch on the dash, they stopped dead, and did not park. Couldn't start them again with dash switch. I have the GM hideaway wipers (2 speed depressed park).
DIAGNOSIS--- I tested the wires going to the wipers and the grounds. They all appeared fine. Here are the tests. The case of the wiper motor and gearbox are always grounded. Test with test light for ground. Check black wire that connects on a separate tang to the wiper cover. It should be ground also. Pull off the 2 wires on the washer pump, which is basically the cover of the wiper gearbox. The yellow wire is 12 volt power when key is on or in accesory. The dark blue wire is ground when you push the washer button on the dash switch. In any event, the washer system runs independent of wipers, so pull off both wires, and tape ends off to avoid sparks while testing the rest. Pull off connector with 3 wires just above wiper motor. Middle one is yellow, must test as power with the key on or in accessory. The light blue wire must test as ground, when the dash switch is in low wiper speed. The third tang is green on mine, and will test as ground also, in wiper high. (I think it also passes ground with key off, but I would have to check my wiper diagram further on this point). There is a red wire going to wiper gearbox also. It must test as hot, ie. 12v power at all times, even with key off. This is what will get wipers to run after the key is off, so they will park.
In my case all wires checked out okay. So I pulled wiper motor out of car, put on bench.
With washer cover off, you will see a green plastic switch on the bottom of the gearbox. Remove the one screw holding it in place. Lift it out a bit. You have one red wire going to one side, and a black with pink stripe to other side, (this latter wire goes into the motor). This must pass power from red to black\pink, when the switch is out of place, as the park position has been avoided.
In my case, I had no power passing thru the switch. Also, test the relay part of the switch. Put power to the middle tang on terminal board, the yellow wire spot, and put ground to the light blue wire tang, closet to bottom of wiper. The relay solenoid must activate to pull the metal part of the switch against it (creates magnetic force).
The REMEDY--- I had no power crossing the switch with it out in my hand. SO I took off the black plastic cover on the back of switch, with tiny screwdriver. It will come off to reveal a set of points. I cleaned the contacts with fine sand paper. Had some black carbon on them. Put cover back on. Tested with voltmeter. I now passed current from red to black\pink wire.
Put switch back in place.
The ultimate bench test----- put power from battery to red wire. ground the case to the battery. put power to yellow wire spot, being the centre tang on terminal board. Put ground to the light blue tang, being one closest to bottom. Voila, wipers fire up and run until ground it taken off the tang on terminal board. Then the wiper motor will continue to run for a couple seconds and park
ADDITIONAL SYMPTOM--Running in and out of park--- If your wiper motor seems to run into park, stop for fraction of a second, then run again, then stop and run, up and down into and out of park, the relay switch must be "adjusted". Big thanks here to Corvette Specialities of Maryland. HE told me how to adjust. Basically put more drag on the armature, by tightening set screw at end of armature, being top of wiper gear box. You will see set screw and lock nut. Putting some tension on the armature will prevent the wiper momentum from forcing wipers out of park position and back into the run position again.
Sorry for long post, but all is fresh in my mind, so I thought I'd share it with you.
 

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Not familiar with Corvette Specialities of Maryland. Who is he? Can find my way to Sensei Earl's site.
 

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Discussion Starter · #9 ·
Corvette Specialties of Maryland. Website is www.corvettespecialtiesofmd.com
Phone 410-795-3180
He specializes in vette dash guages , speedo and tach rebuilds, windshield wiper rebuilds, and clock restorations. I assume he could do chevelle items where similar to corvette.
 

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<BLOCKQUOTE>quote:</font><HR>Originally posted by bhawk:
Corvette Specialties of Maryland. Website is.... <HR></BLOCKQUOTE>

Thanks
 
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