Wiper switch blues

[Jon Woolf]

Hi- I'm in New Zealand, which means no quick trips to the local Chevy junkyard for parts for my '87 Blazer. The wiper switch has (I think) quit. Not only is sourcing a new or gently used one here tough, but it looks like a major drama to replace. Has anyone out there got any suggestions? Use an aftermarket switch and dash mount??? My wagon has had cruise control, but now doesnt- but the switch is still there on the stalk. Is it possible to use that for the wiper, rewiring on the firewall or somewhere to avaoid a teardown?? Help!

 

[Tominator II]

You should troubleshoot the switch and wiring first. Unplug the wire connector from your wiper motor and use a testlight to see if you are getting power to any of the ends when you move the wiper switch. If you are then its probably the circuitboard and/or wiper motor that is bad. If not then you might be able to wire a switch in. Start by doing an accurate diagnosis of the switch.

 

[73k5blazer]

The switch isn't really that hard to get at.
If you remove the wheel and lock plate, it simply disconnects from the bottom part of the column, unscew the hold down screw for it, and the whole thing with harness pulls right out.
The hardest part is fishing the new switches harness down the column, it's routed onthe top of the column, later models had a plastic protective sleeve.
Not difficult though, very straight forward.
The cruise is very seperate from it, if you notice the turn signal arm has a wire on the back side of it, that's the cruise, you can just pull that whole arm right out of it's socket, the wire it attached to a box on the bottom of the column, again, it's a fishing exercise.

But, more importantly, the problem is most likly with your wiper control board rather than the switch. They gobad more often. On the bottom of the column you'll notice a multipin wide connector connected to this little 2x4x1" box with aluminum fins on the bottom. That's the control box. Almost any 80's GM car or truck (US versions anyway, I think Holden used different stuff) has the same box(for that style of wiper, whether it be regular or intermittent). You might have better luck finding another US 80's GM car/truck and ask if you can swap the box for testing.

Here's a generic wiring diagram of how the wipers are wired. Keep in mind, it's generic, I wired my truck from scratch, have no fuse box, but it might help you diagnose your troubles.

http://coloradok5.com/forums/showthread.php?t=174785&highlight=wiper+diagram

Keep in mind the wiper system is a negative switched controlled device. That is, power is at the motor at all times, the switching happens on the ground side of system, via the control box (module). The wiper switch on the column simply controls the module.

And Hey, if your rig is a Right hand drive version, post up some pics. I just love seeing Right hand Drive chevy trucks!

 

[goldwing2000]

That's just the "pulse module". If you don't have delay wipers, that module isn't there and the switch will directly control the wipers.

An easier way to check to see if it's bad is just to bypass it. The two harness ends will plug right in to each other and the wipers will work if everything else is good. I know because that's how mine is hooked up right now.

 

[73k5blazer]

There is module listed in the books for non-pulse vehicles for 1984 and up.

I have one in my '86. Wipers with no pulse, still has the module on the base of the column. It's a different module than ones with pulse, but still is needed.

 

[goldwing2000]

There is module listed in the books for non-pulse vehicles for 1984 and up.

I have one in my '86. Wipers with no pulse, still has the module on the base of the column. It's a different module than ones with pulse, but still is needed.

, too. My '89 has no module at all and it works fine.