Gents

Own a 1980 Vette.
Wipers are not working....

I played around with the wiper dash switch putting it ON and OFF repeatedely and suddenly heard some funny noise coming from the compartment behind the passenger's seat.
I opened the compartment and there is some wiring relays in there !
That's where the noise was coming from. Sounding like an electrical short !
I dismantled the THING and it looks like a relay attached to a small circuit board. There was signs of possible overheet/melting on that board

I took some books out for corvette parts and can't find anything.

What is it ?
What does that thing do for the car ? Wipers only ?
Was this an "add on" buy the previous owner ?
Wiper delay switch maybe ?

Anyone ?

Phil

 

Phil,

Thats the controller. It belongs there. Basically you have the switch,controller and motor.

That part is hard to find and quite expensive. Careful with it. Try to fix it.

I'm not sure if it controls everything or just the delay. My wipers work but my delay does not.

Jim

 

Here is the wireing diagram for that circuit, might help you some. This is for an 81 but should be the same.

 

here is a discription of what all those wires do. There are 4 types of wires in this circuit : power, ground, signal, and control. The power and ground are +12 volts and well ground. The signal is a input to a part as in "the signal wires change the wiper motor speed from off to low to high". A control is an output from a part as the wiper switch controls the wire from 12 volts to ground. I have used this terminolgy as the wiper module has signals going into it and controls coming out of it sometime on the same wire!

Motor
White-power to motor
Purple- low/high speed signal, taken to ground when wipers are on
Gray- High speed signal, taken to ground when wipers not on high
pink- wipers in delay stop position, grounded by switch in motor cover
black - motor ground, connected at bell housing

wiper switch
dark green- delay control, grounded in every position but delay
brown- voltage source to delay adjustment
white/black- variable voltage signal from delay adjustment
gray- instrument lamp power
purple- low/high control, grounded in every position but off
gray/black- high control, grounded in every position but high
black- ground
pink-washer control, grounded when washer button is pressed

wiper controller
dark green- delay signal, taken to ground when not in delay
brown- voltage source from wiper controller for delay adjustment
purple- low speed control, grounded while/after washer is on
white- power to motor, on except during delay stop
brown/white- power to controller
pink- washer signal, taken to ground when washer is on
pink/black- washer control, taken to ground when washer is on or
delay position signal, taken to ground when wipers in delay position
white/black- delay adjustment signal

next installment will be on the wiper controller circuit.


Dale

 

here is the complete drawing


and the picture. I have removed the relay and the power transistor


next will be the test proceedure

Dale

 

I have tested/repaired about 10 of these controllers all had something wrong with them.

Part replacement fail rate symptoms

D1 1N914 10% ?
Q1 MPSA14 10% relay would not switch
D2 1N4148 0%
D3 1N4002 0%
D4 1N4002 0%
D5 1N4002 0%
Q3 D40C1 or MPSW45A 30% no wipers or wipers always on
ZD1 1N4735A 50% delay issues, always replace
Q5 TIP42C 10% no delay
Q6 MJH6284 60% no delay/wipers, replace
IC1 MC14011B 10% posessed wipers!!!

C1 10uf 16V Replace these on spec
C3 33uf 35V
C4 1uf 50V
C5 1uf 50V
C6 1uf 50V


Dale

 

I hook up the thing on a work bench.Red +12 volts black ground


1-Test ZD1
Between pin 14 and pin 7 of the IC there should be 6 volts. Be Careful not to short out pin 7 if you do ZD1 will be shot.

2-test the relay cct.
ground the dark green wire, the relay should switch. lift the ground relay will switch back.

3-washer control
ground the pink wire. pin 3 sould go from 6v to 12v,pin 11 from 12v to
6v, junction of R5 and Q3 should go to 12v and the purple wire should go to 0v.
remove the ground the circuit will switch back after a time delay of 5 seconds??

4-delay control
momentarially touch ground to green pin 8 of ic 6v
momentarially touch ground to pink/black, pin 8 of ic 12v

repeat ground cycle, pin 10 goes from 12v to 6 v

touch green, 12v at junction of Q4 and R15
12v at junction of Q5 R16
12v at white wire, may have to remove relay to see this change.



Dale

 

Man 'O man !
That was more then I expected !

When I go to a corvette shop, what will I call it ?

Will they fix it or simply should I replace it ! $$$ ouch !

Phil

 

The wiper controller is real hard to find but they do turn up on ebay now and then at $100 to $150. The was one ebay just a few days ago. My sugestion to you is find another 80-82 vette that has working wipers and try your controller in it. The wiper switch can be taken apart and fixed as they are getting harder to find and the wiring can be checked especially the grounds.

The circuit drawing that I posted is the only one I have ever seen for this circuit and I had to make that myself. Your wiper controller is fixable and since we both live in the great white north it doesn't even have to go through customs to get it done!


Dale

 

Dale check PM !!!
Phil

 

I have my delay module out and after looking over it very carefully it would appear that (from your picture) what looks to be R16 is fried. Its visibly burnt.

I do not see anything in your description here to indicate replacing this, or what part number this transistor ? is..
Thanks.