I am putting a stereo in my '73 convertible and had to take the dash apart on the driver's side to install the driver's side dash speaker. After the speaker was installed, I wanted make sure all was working properly so I checked the lights. The lights came on and went up and down fine but the wipers began to jump about 3-4 inches. The wiper motor continues to go around causing the wipers to jump up and down. The light next to the wiper switch in the center of the dash blinks on and off at the same time the wipers move up and down.
If I shut the engine off and restart it the wipers don't move but when I turn the wipers on, they go at high speed and when turned off, they begin jumping again and the light blinks on and off as well. This continues until I again shut the engine off. When the engine is restarted, the wipers stay where they are supposed to until turned on and we start the jumping and blinking process again. I would also add that the wipers only have one speed-high. Needless to say it is a bit perplexing and I need to get this resolved before the new tunes are put in and the dash put back together. Any thoughts? Thanks in advance-MrM

 

There's another thread about this same problem. It sounds like you have a loose connection with the wiper switch, have reversed the switch or have a bad ground.

 

It sounds like the black/white wire on the back of the switch (which should be grounded while in off/low speed) isn't grounded or is open between the switch and the motor. The light blue wire should receive ground when either low or high speed is selected, which it sounds like is happening.

First check the switch, to make sure the center plug is grounded in off and low. If it is then check continuity along that wire to the center plug of the wiper motor.

 

Guys, thank you very much for the response. I found a thread about a '72 but it had a wiper door so not all applied but I took a few notes. A buddy of mine says the same thing. The three wires coming from the plug that attaches to the switch (dark blue, light blue and brown) and the single white wire that that goes to the light next to the wiper switch all run into a wiring harness with a buttload of wires. One end goes to the instrument panel and the outher out the firewall. Since the only thing that was disturbed before all this happened was the instrument panel. Guess I will begin there. Looked earlier but didn't see anythong out of the ordinary. Will update later.

 

Wanted to report back on my wiper issue. All indications pointed towards a ground. For the life of me I could not find what had happened to cause the wiper run on or only having the high speed.
I made a new ground wire. Placed one end of the wire inside the connector and slid it onto the switch. The other end I connected to the support brace behind the dash. Wipers turned on and off fine, had park but only low speed. Took the end of my ground wire inside the connector and placed a round connector on it, then secured it to the screw that holds the one side of the switch, grounded the switch. Now I have park, low speed and high speed just like I am supposed to. All working nicely but in the mist of securing my dash, must have knocked a filiment on a bulb loose as my right turn signal on the dash does not light up/blink. All the lights, turn signals and flashers work fine just no right turn signal on the dash. Hopefully I will only have to drop the steering column to have a look and change the bulb and can get on to the bulb. Hope this helps someone as all your suggestions and other posts on this site have helped me. Wish I do more as you guys here are a great help for us inexperienced vette owners. Thanks to ll for your support.

 

Ground wire, eh? Hope your trouble helps me. I've got to go looking for why my wipers do absolutely nothing, especially after I got caught in a sudden storm on a very short test drive. Wow, did I ever wish I had put Rain X on my windshield! Had forgotten how a rippling layer of water makes driving next to impossible... and that was daytime. The pooling water in my lap wasn't fun either.

 

Glad you figured it out

LongRoadHome, what year is your car?

 

'77 with the turn signal+dimmer+wiper lever, been finding out it was only used a few years until 1979. So should be same as-- oops* Have tilting steering wheel but doesn't seem to telescope in or out.

*I mistakenly thought MrM1978 was working on a '78 but see now it was a '73.

A couple wires at the steering column, under dash, had insulation either worn off or cut away so I figured those might have short circuited the wiper or blown its fuse.

Just don't know which wires are which, but I guess by what's been said they could be light blue for low speed wiper. Trying to recall, thinking that was one of the exposed wire colors, other a light brown maybe.

And signals work (except left not self-cancelling) and dimmer worked at first then stopped clicking soon after using that.

Found the fuse for wiper missing but replaced it after wrapping wires in electrical tape. Thought I would put 12V directly to the wiper motor when I know where to apply the power, but will attempt making sure it has a grounding connection before I do.

 

I unfortunately don't know very much about the 77 switch, but the motor should be pretty similar to earlier years (except 68).

Anyways, it's easy to bench test the motor in the car by following Willcox's video:

and



And here is a schematic of your switch that might help

 

update: Jumpered wipers at motor and it lives, now I can at least get through rain if that happens again before a final fix. Apparently mine is a switch grounding problem too.

OP said after their fix: my right turn signal on the dash does not light up/blink. All the lights, turn signals and flashers work fine just no right turn signal on the dash. Hopefully I will only have to drop the steering column to have a look and change the bulb

Best of luck with that fix!

Following is my earlier message, which I thought might relate enough here for others reading:
I already checked for voltage and my meter was all over the place, settling on about 10+ on the middle wire of connector at wiper motor. Was touching one of the other wires there, forget now which one. Middle wire color looks light green instead of yellow. Others are light blue and black.

Nevermind the colors told of there! Wow what a bad memory. Top to bottom, as installed, they are actually a light green then yellow and lastly black (best I can see them anyway).


Also checked on the switch wires to see which colors of the 2 that had bare wire exposed next to each other. Was the light blue and black.
3 more, with 2 of those being black w. white stripe and solid black but a little thinner than the others. And the dark blue wire.

 

Awesome Troubleshooting skills there MrM! We gotta remember this just in case we run across this issue again. The "old Add a separate ground wire to the wiper switch trick" Glad you got it fixed!!
!

 

Thanks guys, this is really a great forum for help and recomdations. The Wilcox videos are really helpful and informative as well.
As with a lot of repairs, once the initial repair is done another (or two) pop up in the process. Not only did my turn signal stop working but so did my courtesy lights. The turn signal problem turned out to be a bulb out of the hole/socket. You all probably knew this already but I didn't, the metal prongs that hold the bulb into the hole on the dash and on the instrument panel ground the light to make it work. So if a bulb is out of the hole, it may still be good but not getting ground in order to light up. Once you clip the bulb in, if it is good it lights up. Checked the bulb and clipped it back and the right turn signal indicator on the dash is working again. Easy fix but had to take the dash apart again to get to it. Tach side hard, speedo side easy.
Replaced the fuse and the courtesy lights once again lit up. Glad that was an easy fix. Replaced all the bulbs on the backside of the instrument panel so I hopefully won't have to worry about them for a good long while. Was very easy now with the dash and console apart, much harder once the stereo is in. Also placed foam inbetween all the vent tubing connections. Hopefully this will give me a much better air flow thru the center and side vents. Checked everything several times as I put everything back together and all seems to be good and working as it should. Looking forward to taking her out for a ride, it's been several weeks. Will really be nice once the stereo is in. Car should be ready for the 4th of July parade and our July lunch run. I really hope this helps someone at some point as it is good to give back when others have been so generous to give. MrM

 

Great news, easier is always better.
Since reading online about trouble with fragile circuit board behind the dash I've ignored what I figure is at least one gauge bulb out.

However, since you mentioned stereo radio, I still need to figure out why mine powers on but speakers are silent. Not looking forward to pulling the console apart since I just got the lower together after fixing window switches. Afraid to touch the gauge panel at all because those work good, but maybe I can get the radio connectors around back checked somehow. I'm planning to put a wiper switch in the lower center console anyhow.

 

If you can remove the RH dash panel, then it's pretty easy to test the RH dash speaker for continuity (to see if the speakers are the problem) and you can easily get to the back of the radio

 

Yup, the right side of the dash is very easy to take off and will give you access to a lot of items, especially the back or the radio and the right dash speaker. For me, I don't think the speakers matched the stereo and at some point someone blasted the stereo and fried the stereo. You could hear a click in the speakers when you turn the stereo on and off but no sound. Could only hear my 7y/o daughter singing. ;-)
I wish I could use the old amp that is in the car as well but a buddy of mine said it wouldn't match or work with all the new stuff. Everything seems to be working better than when I bought the car. So far so good.
Had the car out tonight for the first time in a couple of weeks. Really enjoy driving with the top down, and definitlely ready for some tunes. Keeping all the old speakers etc. for my boy so he can have fun with his first ride. Good luck and don't be afraid to take apart the console.

 

"right side of the dash is very easy to take off"

Easy for you to say, having taken apart the more difficult left side! :clap: Don't know if I dare yet, maybe someday.

I was trying to get a look up under there to see the back of my headlight switch by using my borescope camera and never found it, was trying to see if vacuum hoses still connect to it.
So also looked for dash speakers from below and didn't see them either, not even where the wires might be going to them. Gave up.

In the process of that I was checking back of the Pioneer stereo* and realized a pair of speaker wires goes along the lower passenger side center console and disappeared under the parking brake. Never opened that until now. Discovered the ends were there and only needed pulling out to continue them to the storage compartments where a pair of speakers were thrown in when I bought the car.

Connected them and I have tunes! Lousy sound though, whole thing needs replacing. Think speakers are no good either. And I still want to try and get the dash speakers operational. I also thought speakers might be behind the lower A pillar since perforated panels are there too, flashlight shows outlines that look like speakers there. Just haven't taken that apart yet either. Did see what appear to be speaker wires, dark blue with white stripe and gray. Driver side has solid dark blue but couldn't see a gray, among other wires so not easy to tell what's what.

*Wow. No wonder the sound is weak. Found info about this radio model saying years 1991-94 and only 9 Watts X 4 speakers.

I can guarantee you'll have yours completed way before I get around to mine. Have fun driving with decent sounds.

 

9 watts huh. Probably why they put an amplifier in mine. It's still installed in the dash. Now just a piece of history.
On my '73, I took off the door sills, then the kick panels can come out. On my dash there are 3 screws across the top of the dash and 2 more along the outer edge. Remive those and the dash panel comes right out. Pretty sure yours is similar. My kick panels have perferations as well but no speakers. The 4X6's I bought are a bit short to just plug and play so a slight modofication will need to be made in order to attach the speakers. Need for them to be easily removable as the door bolts are there so future access may be needed. Dash will also need a modification as well.
Going to be changing out the stereo on my '78 as well. Speakers are way easy. Pop off the speaker covers on the top of the dash and remove 4 screws and pull the speaker straight out. Never have to go into the dash, much better design. Rear speakers are on removable panels so very easy also. Hoping to have tunes in the convertable by tomorrow. Glad you have something coming out of your speakers. Something is much better than nothing.

 

"3 screws across the top of the dash and 2 more along the outer edge"

Ah yes, when looking at it I figured that would only be the very beginning. Thanks! In fact I'm already missing the middle top screw above the 'pockets'.

 

Heck, I dropped a couple of screws and they fell straight down. You'd think they would be easy to find but it seems they fall into this dark abyss and you can never find them. I dropped a 1/4 drive 1/2 inch socket in console of my '78 and I still haven't found it. It's definitely a mystery.
Seriously, start with the right side. Take off the door sills, then the kick panels and then the dash. While you're in there you can put some foam inbetween the ventilation tubes to increase your air flow and check out your speakers. When I took the left side of the dash apart, I found my build sheet, very cool. Good luck, let me know how it goes.