bnnnboy

So I've looked around and am coming up empty on how to diagnose the windshield washer pump circuit on my '84. The wipers work but the pump for the washer fluid does not. I've checked the pump (applied 12V directly to it) and it works fine and confirmed that it's not getting 12V at the pump connector. I found some troubleshooting tips for a '96 involving checking voltages at the two connectors on the wiper motor (https://www.corvetteforum.com/forums...ld-washer.html). The voltages I saw didn't quite match the what the post was describing, but I also noticed that the colors of my wires were different, making me think maybe there's a difference in the wiring from an '84 and a '96.

I had to take the wiper switch out of the armrest a while back and flush with contact cleaner to get the wipers working, so I'm guessing the switch either needs more cleaning or the pump switch is broken/unseated, but I'd hate to replace the $90 wiper switch only to find that the $100 wiper motor control board is shot. Any tips on further diagnosis? I may try removing the wiper switch again, but it got a pretty good dose of cleaner before, not sure how much cleaner it can get...

Thanks,
Reed

WVZR-1

Get an FSM - Factory Service Manual for an '84 and use it for your diagnostics.

Hot Rod Roy

The '84 is quite different than the '96 in your referenced post. Unplug the connector on the wiper motor cover. If your wiper switch is good, you should have 12 v. on pin A of the connector when you actuate the WASH function.

bnnnboy

Roy,
Thanks for those diagrams, they're certainly different than the '96 as well as the diagram I have that supposedly applies to 84-96 (either a Haynes or Chiltons). Should the wash function care about which position the switch is in (Mist/Off/Pulse/Low/High)? If I'm reading that diagram correctly (unlikely), it looks like in the Mist and Off settings there's 12V going between the light and the 24K resistor that would give some voltage on Pin A of the cover connector. Before when I did some diagnosis with the ignition ON but the engine not running, On Pin A I saw 11.8V on the Mist and Off settings, 10.5V on the Delay, and nothing on Low and High, regardless of whether I pressed the Wash stalk button. Sounds like I need to pull the switch, give it some more TLC, then maybe replace it if it's still acting up.
Thanks,
Reed

Whaleman

I have a 96 and this was my problem. Dan

Cruisinfanatic

90% chance (or more) you have a bad switch especially since you've had a problem with it in the past

xrav22

Keep cleaning!
Every rain I have to work my switch a little but then all functions work.
Pour water on your winshield and keep working the switch, of course pushing it down causes pump action. Clean it again too.
Good luck

Hot Rod Roy

XRav and I have a problem: Being in SoCal, we don't get to exercise our wiper switch very often!

xrav22

Very true I exercise it .

It is actually a good setup.

Slide down for single wipe action
Push button for 5 wipes and pump
Slide up between 1st position for timed wipe
1st click slow
2nd click fast
Slide down to bottom to end

Hot Rod Roy

Anybody, or anything that says the '84 and the '96 are the same should probably be ignored (especially if the title starts with H or C)! The engineers were very busy!

I agree that diagram is confusing. I have also confirmed there are errors in the '84 FSM. (PULSE in the diagram is DELAY on my switch, among other things.)

Okay. I tested my own '84, which works fine. The brown wire (pin A) of the cover connector should get 12 v. for the washer pump with the wiper switch in the DELAY/LO/HI position and the WASH button is pushed. So it does sound like you've got a switch problem. Are you cleaning it with electrical contact cleaner?

If that's not the problem, that narrows it down to the circuit board in the motor, since you apparently don't have 12 v. on the pink (pin C) to the wiper pump in this mode. You probably want to re-test if pin A tests good with this understanding.

bnnnboy

Agreed, I need to re-check the voltages this weekend. I suspect it's the switch as well, but the voltages I was getting last time seemed to imply a control board problem. I've squirted copious amounts of electrical contact cleaner in there before, but I seem to recall I was just spraying through the slot for the switch slider, I don't think I disassembled any further (if that's even possible).

Thanks everyone for the suggestions, I'll let you know how it goes. Hopefully I can make better sense of it this weekend.
Reed

xrav22

Dont forget to clean the plug, that helps too. May even use some sandpapee ,no wire brushes.

bnnnboy

Good call! Or more contact cleaner!

bnnnboy

Just a quick update on this problem. I removed the switch again and flushed with lots and lots of contact cleaner and compressed air. I was able to get the wash switch to engage about 10% of the time in the LO position, but nowhere else and no amount of additional cleaner or air made it any better. Looks like I'll be buying a new switch... stay tuned!
Thanks,
Reed

bnnnboy

Another update (and resolution)!

I installed the new switch and the washer worked fine, but the Lo and HI wipers didn't work. Figured out that the back plate of the switch wasn't held in place well enough, so it worked when I squeezed it closed. Since I had nothing to lose with the old switch, I cut off the retaining tabs, removed the back, and cleaned up all the contacts with steel wool. The washer contacts looked about like the outside of the statue of liberty, no wonder they weren't working! I made some metal pins to hold the back of the switch on and now the old switch works just fine! It's all back together and working like a champ.

Thanks for the help everyone!
Reed

xrav22

Engineering!