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My 77 windshield wipers stopped working. No power to the wiper motor so I suspect the wiper switch is broke. I have a tilt steering wheel and the replacement switch is not available since this switch is unique for the 77 only. My turn signals work properly.
My question is, can I add a simple switch under the dash to operate the wipers. If so can I wire this new switch to the wiper motor without getting into the steering column. How would I wire this new switch.
Do you have voltage at the motor connector yellow wire? ignition switch in accessory or on position?
It all starts there. If no power at yellow wire check fuse panel lower right side wiper fuse, 25 amp.
Last edited by bmotojoe; Jun 15, 2018 at 10:33 AM.
Probably wouldn't hurt to check the top and bottom wiper connector pins for continuity to ground when you move the switch. Iirc, on low speed both pins a and c should have ground, on high only pin c should have ground, and as mentioned earlier pin b should have +12v regardless of switch position as long as the key is on. (Calling the pins a,b,c from top to bottom)
if all that's missing is the +12v, the switch in the column is working fine. It's possible to test by jumping 12v to that middle pin and trying the switch.
Last edited by DB Cooper; Jun 15, 2018 at 11:02 AM.
Pulling a plug and checking continuity between two terminals and ground is also a whole lot less effort than wiring an additional switch, especially if the trouble ends up being between the fusebox and that center hot terminal.
Thanks for the suggestions. I do have 12 volts at the yellow middle wire. The wiper motor is grounded. With the key in and switched on the bottom wire is grounded with the wipers turned on or off. The top wire is not grounded with the wipers turned on or off.
That does indicate the switch as the problem. If you jumper the top terminal to ground, do the wipers run? If so, that top pin and ground are what I'd run to an additional switch (assuming you really don't feel like tearing into the column). That would still be using the same fused power circuit, it would be the least work to install, and the easiest to put back to stock later if you chose to.
Last edited by DB Cooper; Jun 16, 2018 at 02:29 PM.
I just went through a similar wiper issue, except it was the middle wire intermittently not getting 12v. Since both sides of all the fuses had 12v with the key on, I figure my issue is likely on the back side of the fusebox itself. I spliced into the middle wire and ran a jumper through the firewall to the fused side of the heater/ac circuit (since my ac was deleted and heater core bypassed before I got the car)... so that circuit is still fused, and isn't going to draw anything like 20a. I'd have used the wiper fuse instead, but can't be 100% sure which one it is.
bottom line is, I simply don't feel like pulling the fusebox off the firewall and testing / sanding every terminal on the back side right now just for the wipers. So I bubba'ed it in a way that's safe and simple to correct at a later date.
I just went through a similar wiper issue, except it was the middle wire intermittently not getting 12v. Since both sides of all the fuses had 12v with the key on, I figure my issue is likely on the back side of the fusebox itself. I spliced into the middle wire and ran a jumper through the firewall to the fused side of the heater/ac circuit (since my ac was deleted and heater core bypassed before I got the car)... so that circuit is still fused, and isn't going to draw anything like 20a. I'd have used the wiper fuse instead, but can't be 100% sure which one it is.
bottom line is, I simply don't feel like pulling the fusebox off the firewall and testing / sanding every terminal on the back side right now just for the wipers. So I bubba'ed it in a way that's safe and simple to correct at a later date.
Very good troubleshooting information on the 77 wiper system.
To save you a little time:
Bulkhead side of panel, wiper motor yellow switched wire. Late 77 manual dash harness.
78 later- thanks to Willcox for laying out the colors-
So basically- Blue (in above diagram) = purple
and Green = gray on the later motor
A-No connection
B-No connection
C-Pin 2 on switch ( marked Blue above)
D-Pin 5 on switch (marked Green above)
E- Ground
F-to switch to ground to control washer
G-Ground
H-No connection
I- No connection
So- will need another switch to ground to control washer...
Last edited by Richard454; Jun 16, 2018 at 11:21 PM.
I am guessing that people do know how to check the wiper switch itself for this 1977 while it is still in the column.
When the connector is disconnected like what is shown in the photo in POST # 15 and 17. An ohmmeter can tell you right away if it is good or not when obviously checking the end of the connector that goes to the wiper switch in the column and NOT the car wiring side.
If it is bad...then Richards option is a really 'tasty' good looking option.
That does indicate the switch as the problem. If you jumper the top terminal to ground, do the wipers run? If so, that top pin and ground are what I'd run to an additional switch (assuming you really don't feel like tearing into the column). That would still be using the same fused power circuit, it would be the least work to install, and the easiest to put back to stock later if you chose to.
I did jumper the top terminal to ground and the wipers do run and when I pull the jumper the wipers stop and park themselves. I will get a switch and wire as shown in the following posts.
77 wiper switch work around
