Welcome to the Corvette Forums at the Corvette Action Center!

78-82 Delay wipers-NEED HELP!!!!!!!


Well-known member
Jul 3, 2001
Auburndale, Florida
1969 Killer Shark
Everything was going just fine on my wiper conversion, until I realized that all the schematics I have only showed me what the switch is doing. I have no idea which wire to connect where. I really need your help. If you have delay wipers on a 78-82 I would be your best friend if you would please,

Probe your harness with a test light key on/off, wipers in slow, fast, mist, etc. and tell me which one correspond with letters ABCDEF on this picture. Don't worry about the colors as that alone won't tell me anything but, you can add that in if you would like.

Thanks a million, I owe you guys one for this.

:L Either you find that or start experimenting, eh Chris? ;)

_ken :w


I'll fax you a copy of the schematic for the wiper delay on Monday. I have the entire schematic at work. Maybe I can get one of my Tech-aides to scan it in, but it might lose some detail in the process.

......... Bob
Hey Nut,
the schematic probably won't help as about 50% of the electric
is inside the washer pump.also when Chris and worked on it today there was an additional problem of the motor running backwards slowly when the switch is on high.This one really cracked our brains today:L
Understood. I'll see if I can find my tester and probe it out.

.......... Nut
Looks like I missed the boat on this one.

First, my excuse. It is true, and Garry will second me when I say that the Corvette manual 68-82 that I was reviewing showed the "typical later model" with the delay circuit and it is a match for the 84-89.

Here is what is strange (oh yes, I did spend many an hour perfecting the 84-89 delay switch mount) Redmist e-mailed me a non delay 1978 schematic. What I have learned from it is that the swtich in the dash works off of ground and the motor has the 12+ plus all the time to the wash and motor. The 84-89 works off of a 12+ at the switch sending out a variety of different 12+ signals to activate the motor and timer. At the same time, I don't know of a late model C3 would or would not be the same way with DELAY.

Okay, I ordered an 89 wiper motor. I know they are different but they do have the same bolt mount pattern. The trouble is most don't come with the cover. I will find out later if this one does. In the mean time, I have a crazy idea to change my switch to ground instead of 12+ and see if it will operate this motor. However, the delay is not going to work that way the best that I can gather.

I will keep you posted.

I think the 89 wiper motor is the way to go. Since you have the switch in there are 2 resistors that control the delay relay... so switching the switch polarity will not work.

This is my best guess ( based on Fact schematic 1988 )


Three connectors at wiper motor
PIN B Ground ( Black )
PIN C Output+12 ( Pink ) to washer motor
( external )
PIN A Input for Delay( Brown ) Looks like varying voltages( In pulse ) under 12v and in Low &        in High ( cont ) 12 volts. Pulse=delay
PIN A Jump from C3 PIN B ( Gry.Wh)
PIN B Input Washer control & Park relay control
(Light Blu) +12 when washer is switch is pressed or In Pulse/Low/High/or Mist
Pin C Input Park relay power& Aux power for Timer Control( Gry ) +12 in Mist/off/pulse or LOW position.

PIN A Input +12 ( Purple ) in HIGH position ONLY
PIN B Jump to C2 pin A Low speed & pulse control        to motor 2nd winding (This is a gray which        jumps to the gray white.)
C3 has no other connections

It looks like
C2 Pin B is the control line to override the park relay ( will not park if line is High and will not start if line is low...)

C2 Pin C is the power line to the low speed side of the motor ( Internally) Via Park relay comes out on C2 Pin A then to C3 Pin B to motor (low speed)

C1 pin A is a varible resistance the closer to +12
the less delay between wipes.

If you had 12 volts between pins A & B of C3 the motor could run backwards if the polarity was wrong.

I'll dig some more.

Mike, thanks for putting all that together. I am having trouble finding a reasonable price and availability on a 89 style motor that has the front circuit board cover included (new/rebuilt).

I checked with Napa today and they had a 78-82 delay wiper switch in stock--kind of a fluke. In fact, it was in a Delco box at the same discounted price I usually get from the dealer.

Redmist shot the 78 delay wiper schematic my way. Thanks a ton, I owe you big time. Anyway, low and behold I find out that the C3 uses a controller assembly to sort out the wiper action. Napa does not carry those, but says they are only about $20-$30 at the dealer.

Okay, good enough. The only other big headache is getting the pigtails as you will find the schematics do not show you on the switch where the wire goes, only the pig tail. So, I shot a message to a fellow that works with a local recycler to see what he has in the bone yard.

One way or another I am determined to put delay wipers on this stupid car and make it look factory clean. I actually lost my temper with it this weekend, and that is no good. The good news is, I was able to get creative and insert the 78-82 switch into the same hole I custom built for the 84-89---so not a total waste of time.

Now, maybe this week I can drum up the rest of the parts and finish this out by next weekend. Believe it or not, this wiper circuit is going to take me about three combined weeks of messing around to get it right.

So do you need the info for an 81 wiper circut?

I think you should be able to get a complete wiper motor assy for about 75 bucks. That's what I paid for mine.

I too have problems with my delay wipers. That feature does not work. Do you think it might be the relay or the wiring in the motor. Any help would be great.
Thanks. :)
There are three main components; switch, relay module, wiper motor. You might take the cover off the wiper motor and inspect the switch inside. It is what that pink wire goes into. I don't know how to describe it, but maybe it is dirty or broken.

The bad news is, that for 78-79 and into 80 the control module is not longer available from G.M., so you will have to hunt up an original. I don't know what is different from that to the 81-82, but they are different part numbers.

You can get a new switch for around $30, so you might want to just replace that first and see what happens.
Thanks :)

Thanks for the info and advice. I will try that. :)
DDK Tech

I was catching up on my magazines the other day when I finally read the Novmber 2001 issue of Mustang Monthly. Then I see this company that makes intermittent wiper control for early 'Stangs. It a simple design that will make all of us envious. Please drop these guys a line, as they make components due to customer demand. "If you build it, they will come." DDK Tech --Bullitt

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors


MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Top Bottom