Rear wiper gremlin; help needed

[Kernal]

Noticed while driving that my rear wiper was intermittantly sweeping, but the stalk control was in the off position?? I tried a few different positions of the stalk and the wiper did work when put on continuous, but continued to sweep intermittantly when put back into the off position. For a quick fix I pulled the connector that ran from the rear wiper motor to a small box (?wiper relay or controller?) located on the left side of the lift hatch, and no more problem, but of course the rear wiper doesn't work now. No other electrical gremilins happening. I searched but couldn't find much other than one thread about someone who had a short in a wire bundle above the headliner causing problems with the rear wiper and some lights. Any ideas?

 

[Kernal]

Anybody?

 

[nicksr]

I have problem with my rear wipe too. only sometimes it works fine and other times it doesn't. when it doesn't work, it also causes the LED Stop bar to not work also. Very inconvenient when it happens at inspection time.

 

[Wrench]

Happens to me. But only when it rains. But I rolled my truck so go figure.

 

[lndcruz]

Maybe it's a long shot but it might be similar to what happens to many Volvo 240 station wagons. The wires in the hatch get frayed and short out(hens it only happens some times). I would just check all the wires that go though the hatch to the body of the car.

 

[Kernal]

Seems like I read something on mud once about problems with the ?control box the wiper motor plugs into?? I'll check the wiring.

 

[gotmud]

X2 on wiring issue. Mine had a similar problem when I first purchased. Turned out to be a bad ground connection. I cleaned up the ground point and the problem went away.

 

[scottm]

X2 on the ground wire, that did some weird things to my entire electrical system. I stuffed a fresh wire up through the rubber boot in the hinge and down to the jack storage area, following the original ground wire.

 

[Kernal]

Newb question; what color is the ground wire and whereabouts should I look?

 

[leonard_nemoy]

I am chasing this same issue, I am really struggling to find the ground for the rear wiper via the Toyota wiring schematics. Could someone describe the color and where exactly to find the ground. I checked the wires at the hatch and inside the hatch and everything looks great. But the wires in the rear quarter area are all covered in dirt, dust, and road grime. The PO trimmed the fenders and never sealed the area so evidently it has had a lot of water and who knows what else make its way into the rear quarter panels.

Thanks

 

[Kernal]

These may help:

Link to a digital copy of the factory EWD:

https://static1.squarespace.com/static/51a65a4de4b00037e6b3e3be/t/55ff7b15e4b08adf62131e69/1442806549877/1996+Toyota+Land+Cruiser+EWD.pdf

 

[retlaw]

The 97 LX EWD shows the wiper motor ground as location BF white/black and the stalk ground as location ID white/black... But it seems to me that if the grounds were bad or intermittent it wouldnt work correctly when you wanted it to but to operate when the stalk is OFF would seem to be a shorted / corroded connector....Connector BV1 is in the left rear panel and contains the wire that runs the wiper intermittent operation...if it is grounded the wiper will run.
Its Blue/Black Pin 2... there are 5 wires in this connector. It also looks like Pin 5 Light Green makes the wiper move when the stalk is ON or the washer is used...
The rear wiper relay is in the hatch and these wires control it.... There are connectors in the hatch that are between the relay and BV1 and a short there could also make the motor run but from your description of the left rear panel I bet the problem is with BV1..............Not sure if LX and LC are the same.

 

[leonard_nemoy]

Thanks @retlaw when it comes to electronics, specifically wiring diagrams, I know nothing. I am sure you are correct though because I tore into the back left panel under the factory jack and all the wires and connectors in that area were covered in grime. I used some silicone to try and waterproof the area because there were some holes from trimming and removing the fenders and flares.

I am definitely going to need to pull apart the connections for an inspection and cleaning. Now I know exactly what wires to double check when I get in there.

 

[jonheld]

If the wiper motor is running with the stalk switch in the off position, then it is unlikely a bad ground. A bad ground would result in no wiper motor, not constant wiper motor.
There is a rotary switch inside the motor housing that can fail. When that happens, the wiper continually wipes regardless of stalk switch position. a new wiper motor will cure this.

 

[BILT4ME]

If the wiper motor is running with the stalk switch in the off position, then it is unlikely a bad ground. A bad ground would result in no wiper motor, not constant wiper motor.
There is a rotary switch inside the motor housing that can fail. When that happens, the wiper continually wipes regardless of stalk switch position. a new wiper motor will cure this.

Since Toyota switches the ground side, if it was grounded it would run constantly, right?

 

[retlaw]

Since Toyota switches the ground side, if it was grounded it would run constantly, right?

I see your point but when someone says "bad ground" I think of a designed ground point that is missing, intermittent or corroded (high resistance)...NOT an otherwise good circuit that has a ground somewhere that it shouldn't. I would call that a "short".

 

[retlaw]

I see your point but when someone says "bad ground" I think of a designed ground point that is missing, intermittent or corroded (high resistance)...NOT an otherwise good circuit that has a ground somewhere that it shouldn't. I would call that a "short".

And yes, the ground IS switched and depending on where the ground is in the circuit (by design or fault) the wiper will run. If the designed ground is "bad" then the complaint could be something like "wiper doesnt run or is intermittent when I want it on full-time" but not "it works ok when I want it to but comes on when I don't want it to". The designed ground, good or bad, cant make it run when the stalk is off. I think they call this "semantics" and correctly describing a problem for others to diagnose is indeed challenging.

 

[jonheld]

The rotary switch in the motor housing is what allows the motor to return to the wiper "rest" position when the stalk switch is turned off. When this switch fails or becomes intermittent you have wiper motion regardless of stalk switch position. Both front and rear wiper motors work the same way.
I think that's the issue that the OP had, but I'm not certain what issue @leonard_nemoy is having.

 

[retlaw]

Yes! I now see that rotary switch for both front and rear motors in the EWD. I agree... for the front this switch sends 12 volts to the wiper motor via the stalk circuitry when the stalk is off until the wipers return to rest and the switch breaks the circuit. Both front and rear motors have constant grounds. The front motor is controlled by 12 volts from the stalk (and rotary switch) and the rear is controlled by 12 volts from the rear wiper relay (and rotary switch). This relay for the rear wiper is operated by ground switching from the stalk with connectors in the left rear quarter. So, I was partly wrong about ground switching....its really only the rear wiper relay that's controlled by ground switching.
Interestingly, both motors have a circuit breaker in the ground leg. I guess that's for when I turn on the wipers when they are covered in snow or ice!

 

[leonard_nemoy]

The rotary switch in the motor housing is what allows the motor to return to the wiper "rest" position when the stalk switch is turned off. When this switch fails or becomes intermittent you have wiper motion regardless of stalk switch position. Both front and rear wiper motors work the same way.
I think that's the issue that the OP had, but I'm not certain what issue @leonard_nemoy is having.

Very interesting stuff. After I get around to pulling the plugs apart in the driver rear quarter and give them a good cleaning and inspection I will update and if it happens again than I will have to check the rear motor. That being said I am pretty certain it has something to do with the plugs under the jack. They had clearly been getting exposed to road moisture and grime. It has only happened once and I had been driving for a couple of hours on snowy wet salty roads. Everything in the back hatch looked very clean and seemed to be in great condition compared to the drivers rear quarter panel.