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Amedee, Buick Mechanic
Category: Buick
Satisfied Customers: 24120
Experience:  ASE certified Technician advanced level specialist. Wisconsin certified emissions state inspector
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1999 Buick lesabre: windshield wiper..the fuses..wiring diagram

Resolved Question:

1999 Buick LaSabre windshield wiper stopped working when the windshield got heavy snow. I checked the fuses- 8E 25A fuse was good. Looking at the wiring diagram its most likley the switch, right?
Submitted: 5 years ago via AllDataDIY.
Category: Buick
Expert:  Amedee replied 5 years ago.

Are you sure there is no power going to the switch? Did you check it with the key on, wiper selector on high? Did you use a voltmeter or a test light?

Do you need a wiring diagram of this circuit?
Customer: replied 5 years ago.
key was on. switch was on high. I have the wiring diagram. I used a led test light.
Expert:  Amedee replied 5 years ago.
If there is no power going into the wiper motor with the wipers switch on high (and key on), then I would be willing to bet that you are right on track. Chances are the wiper switch is bad. Obviously, be sure that there is power going into the switch on the yellow wire.
Customer: replied 5 years ago.
I knew that already. What I need to know is how I can hot wire the motor with a direct switch and resister. I am afraid of blowing out the module. I cant afford a switch replacement.
Expert:  Amedee replied 5 years ago.
The only way you can how wire the motor directly without the switch in place it to jump a wire from yellow to purple. But if the yellow wire is hot all of the time, then the wipers will un all of the time.
Customer: replied 5 years ago.

I don't remember the wire colors going to the motor. Is the purple wire going to the motor? Do you mean bypassing the module and go directly to the motor?

Expert:  Amedee replied 5 years ago.
No.. by passing the switch and going right to the motor is what I mean
Customer: replied 5 years ago.

So i understand that the wiper module is bypassed. What are the wire colors going to the wiper motor itself?

Expert:  Amedee replied 5 years ago.
Here is a diagram

Customer: replied 5 years ago.
I have that diagram but it doesn't show the plug going into the motor. There is a 6 wire plug going into the module and there is another plug going into the motor itself. The wiper module has a yellow wire going to it I know. I am not at my car now so I can't determine the wire colors going into the motor. I know there are at least 3 wires going to the motor itself. Which ones need to have voltage going to them? Which wire needs the resister to make it move at medium speed?
Expert:  Amedee replied 5 years ago.
The yellow purple and black wire goes to the wiper pump.

The other wires go to and or from the module.

The pink wire from the switch to the module is the wire that gives the module a signal for intermittent wipers.
Customer: replied 5 years ago.
Ok, maybe that other plug was to the wiper pump. I don't know. So I have to apply voltage to the module wires. You said yellow and purple need to be hot. I don't see a purple wire going into the wiper module plug connector #12059572
Expert:  Amedee replied 5 years ago.
The purple wire goes to the wiper motor... look at the diagram.
Customer: replied 5 years ago.

The diagram doesn't show the seperate plug going to the motor. There are two plugs going to the unit one to the motor and one to the module. You said apply voltage to the purple and yellow wires. I realize now the other plug was not the wiper washer pump.


Expert:  Amedee replied 5 years ago.
If there is no power on the purple wire, then yes, try to supply power to this wire and see if the wipers work.
Customer: replied 5 years ago.

so if I apply power to the yellow and purple wires, which one needs a resister to make it run slower?

Expert:  Amedee replied 5 years ago.
Neither... it is the pink wire that has a resistor on its circuit inside the switch.
Customer: replied 5 years ago.
right, but i want to buypass the switch and run a hot wire to the wiper motor. I want it to run at a slower speed.
Expert:  Amedee replied 5 years ago.
I know... I am saying I do not think you will be able to do this.

THe only thing you could do it after you find out the resistance of the resistors in the switch, go to radio shack and install one of these resistors in line on the pink wire. THe only problem is if that odes in fact work, then you will only have one intermittent speed.
Customer: replied 5 years ago.
it says on the daigram that medium speed is 350k ohms right? So if i run a wire from a 12 volt supply with the reisister in series feeding the yellow and purple wire to the wiper motor it should run at medum speed right?
Expert:  Amedee replied 5 years ago.
Close.. the purple wire is full battery voltage all of the time. The only thin you would need to do (if the switch is faulty) is install a resistor in line with the pink wire and that should do the trick. Or.. just run another wire from battery voltage with the resister in line and hook it up ot the pink wire and that also should do the trick.

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