[Silentlion_69]

The windshield wipers on my truck, (1985 GMC Sierra C1500) have been acting wierd, every time I start my truck they turn on for like 4 or 5 swipes back and forth. whats going on? do I need a new wiper motor?

 

[docvette]

Switch

Doc hereimp:

HAPPY THANKSGIVING!

It sounds like you may have a short at the switch, or column harness .

It sounds like after start, power is getting to the wiper switch, maybe the delay side, from the "Start" line as it goes through the steering Column. fires the wiper delay then after "Start " is relieved of power (Key position returned to "Run") The Wipers "cycle" then stop.

Check your harness in the column and the plug at the bottom.

Also if you Have a relay, you can back check from there.

If you need to function test it while troubleshooting but don't want to keep cranking the engine, pull the "S" wire on the solenoid, the circuit will work but the starter won't engage..It will keep your battery fresh.

Good luck!
Happy Holidays!

Doc imp:

 

[willowbilly3]

I had the delay module go bad on my 85 Suburban and the wipers got erratic. Also check all the grounds. Chevy pickups of that vintage are notorious for wiring glitches and many of them are due to bad underdash grounds. These can be hard to find but some of the bodyshop manuals do list the locations for them.

 

[302 Z28]

Not related, but our old 97 Tahoe wipers started behaving eratically. On delay they would just stop and start on their own, or they would start a sweep and stop. One particularly rainy evening on IH10 from Houston they quit altogether. Next day I could not get them to work at all. Checked with Auto Zone and a new wiper motor was $134. Our 97 Tahoe at the time had about 50K on the clock, so I though I would just check with the Chevy dealer about a little warranty work...he said sorry, oh well it was worth a try. Got on the net and did a search for any TSB's on the 97 Tahoe. Sure enough a TSB on intermittent wiper operation was listed. Went back to the Chevy dealership to obtain a copy of the TSB. It said the wiper motor PC board had a problem with solder joints breaking right at the joint to the motor. Pulled the motor and removed the cover. Got out my magnifying glass and found a broken solder joint. My trusty Weller fixed it right up. Been working great ever since.

Vince