Windshield wipers (1 Viewer)

[jmylie]

My windshield wipers on my 79 FJ40 no longer work.

I have power thru the fuse.

I unplugged the wiper switch and tried to test power to the switch but no luck.

I used a 12v tester which has a pointed probe and a clip to attach to ground.

I touched all 6 contacts in the plug going to the switch and the tester did not light up.

Key was turned to acc.

So, I'm not sure if the switch is bad or there is a broken wire somewhere. Does the wiper circuit have a relay?

Any help is appreciated.

 

[73FJ40]

Could be a grounding issue.

Try running a temporary ground wire directly from the ww motor to the negative battery terminal.

 

[spotcruiser]

Could be worn brushes.

 

[jmylie]

I did bring the motor in for an inspection. Mechanic found a broken wire but said brushes looked fine.

He did fix the wire.

 

[spotcruiser]

Power goes to the wiper motor. The switch provides the ground.

 

[jmylie]

I attempted to connect the wiper motor directly to the battery.

Schematic indicates light blue wire is power.

Motor did not turn.

Did I connect this correctly? If so, I assume I need a new motor or this one rebuilt.

 

[spotcruiser]

No.

12V goes to that light blue wire as shown.

Connect a wire from ground or batt- to one of the speed wires (blue/red for slow or blue/black for high). You can connect the ground wire to one of the speed wires at the motor plug.

I attempted to connect the wiper motor directly to the battery.

Motor did not turn.

Did I connect this correctly? If so, I assume I need a new motor or this one rebuilt.

 

[spotcruiser]

Maybe this will help.

 

[jjenloe]

I normally don't suggest buying things, but if your going to do any electrical work, get a Powerprobe. You can add power and ground to get things to work.
I had this same problem with my wipers. You have to ground the motor and then add power to blue wire. If the motor doesn't work, try gently taping it with a wrench. Sometimes the shock will bounce the brushes back into place. Taking the motor apart isn't that difficult. Here is a Youtube video that shows how to do it.

 

[jmylie]

Ok, grounded the wiper motor, hooked power to light blue wire and did red blue to ground and success. The motor turned.

Is there an easy way to test the switch or just replace the switch?

Thank you for your help.

 

[TCEd]

May need to check the wiring from the switch to the motor. Also the connector for the switch can be connected in reverse, there is no keying on that connector.

 

[spotcruiser]

Most likely the switch is not grounded well. As I said, the switch provides the ground. It connects whichever speed is selected to ground, which completes the circuit. The ground at the motor is for the "Park" feature. Make sure the w/b wire to the switch is properly grounded.

 

[jmylie]

Based on the schematic above, the wb wire (white/black) from the switch goes to ground.

Any idea where that ground is?

 

[spotcruiser]

It's been many years since I stuck my head under there. I think it comes from the harness, but I don't remember where the actual ground point is. Just unplug the switch connector and verify that the w/b wire (connector) on the harness side is well grounded. Then verify that the w/b wire (connector) from the plug to the switch is continuous. Might as well clean both sides of the switch plug and both sides of the motor plug as best you can. And make sure the wires on both sides of the plugs agree, as TCEd mentioned.

While you're at it, pull the switch out of the dash and clean the mounting surface of the switch and dash hole (back side), and the windshield washer "contact" to ensure that your washer pump gets a good ground. The washer pump contact is that little brass arm near the front of the switch that rotates with the switch shaft.

Note: A 79 might be different than the 76s and 78 that I have.

Based on the schematic above, the wb wire (white/black) from the switch goes to ground.

Any idea where that ground is?

 

[spotcruiser]

By the way, have you tested for 12v on the blue wire at the harness side of the motor plug (ignition ON)?

 

[jmylie]

Thanks for the suggestion. I tried. I put the ground to the dash and a probe to the blue wire connector.
Nothing. Tried again with a multi-meter, black to the metal dash, then black to the white/black wire.

Zilch.

Difficult because the connector is a good 4 inches in from the dash. Even with the radio removed it is hard to see with your hand in the way.

Yup, ignition key turn on.

 

[spotcruiser]

You do not have power to the blue wire on the harness side of the motor connector with the ignition on? I'd recheck the fuse and take it out of the fuse block to do so.

 

[jmylie]

Fuse was the 1st thing I checked and I did replace it even though it checked ok.

But I'll double check.