Windshield Wipers out of wack?
 

Hello, I have a 2000 Obs k3500, my wipers will work on all delays but they stop wherever they want lol, sometimes in the middle, sometimes upright, sometimes if im lucky they stop where they should at the bottom.

whats causing this? The squirter is intermittent as well, should that have any relation to this issue?

Thanks in advance!!!

Re: Windshield Wipers out of wack?
 

I'll be interested to hear this also. My 81 has the same issue, so maybe it is similar problem even though the year grouping is wrong. Hope you find your answer.

Intermittent supply more than likely
 

Since both items are stopping intermittently, chances are likely the common voltage to them or the common ground to them is dropping out on occasion.

Here's the wiring diagram
http://s1371.photobucket.com/user/St...kwzvv.jpg.html

Sorry for the quality but this site won't allow pics that aren't posted elsewhere.

My opinion is the voltage is dropping out occasionally on the supply side. You'll notice there are 2 separate yellow wires from the fuse. One to the switch and the other to the motor. Also notice the voltage to the pump comes out of the motor module. It's not like a problem after the motor to the pump since the motor stops also. If that were the case, there would have to be 2 separate problems which is not likely.

Since both items are intermittent, they must be loosing the common supply. NOTE that they could also be loosing ground intermittently as well.

Start checking the supply Yellow wire to the switch for intermittent dropping out.

Also check, if needed, the ground to see if it is intermittent.

The ground point for the washer/wiper motor is on the left side of the Ins Panel, below the fuse block on the tie bar.

Start by simply pulling out the fuse and reseating it. While you do that, pay attention to the force it requires to pull and put it back. Sometimes the female side of connections relax over time. Many times the male portion, in this case the fuse, gets oxidized and it only requires pulling and replacing to clean it.

If that doesn't work, try the same thing with the connections at the switch and the motor.

Hope that helps.

Re: Windshield Wipers out of wack?
 

Just went thru this very same issue on our Old Body Style '99 Tahoe. Googled the term "Tahoe erratic wiper operation" or similar and found several Utube videos about changing the "wiper pulse module board". VERY simple on our Tahoe. Three screw on the cover of the wiper motor and dis-connect a elec. plug. Plug in the new pulse board, replace the cover and presto- problem was solved in maybe 30 minutes. Got the pulse board at our local parts house, think it was just under $25. Not sure you have same problem but definetly sounds like it. Check my posting in the GMT800 99-06 message board. Hope this helps.

Re: Windshield Wipers out of wack?
 

This

Re: Intermittent supply more than likely
 

Helpful reply, thank you!

Re: Windshield Wipers out of wack?
 

Thanks!

Re: Windshield Wipers out of wack?
 

known issue with circuit boards replace wiper module in firewall.

autozone or other stores sell the boards.

Re: Windshield Wipers out of wack?
 

Its the circuit board for sure.

Re: Windshield Wipers out of wack?
 

1981 Is a different motor setup from the T400 trucks.
Have you asked in the 73-87 forums?

For the OP sounds like it's the park switch circuit on the motor control board. You'll see two spring contacts with tungsten contacts, like breaker points, on the motor side of the control circuit board. IIRC one of these rides on the park cam and shuts the motor off at the bottom of the sweep...
T400 wiper problems are usually a board problem at the harness plug connection... either cold solder joints or broken and separated traces.

Re: Windshield Wipers out of wack?
 

Yeah I caught myself after I posted. The old age is getting to me , the years are all running together :lol: