Rear Wiper

[ryanrtxtx]

Hey Guys,

Rear wiper on my 1994 Land Cruiser does not respond at all. Wondering if anyone on here could give me some detailed steps to figure out if I need a new motor or if there is something wrong between the switch and motor. I'm not a mechanic, so the more detailed the better if you know how to diagnose this problem. Thanks in advance.

Ryan

 

[KliersLC]

I'd start with the fuse and go from there. If you have a multimeter, this is a pretty straightforward diagnostic.

1. Verify the fuse is good (I don't remember which one, should be labeled--if not, check them all.
2. Verify power to the wiper motor. Check for power with switch off, and switch on; verify grounds are good. You will have to pull the inside panel off of the upper hatch. This is also a good time to make sure that the mechanical connection to the rear wiper hasn't come loose.
3. If you are getting power to the motor, then your issue is likely the wiper motor itself.
4. If no power to the motor, the right thing to do is to work backwards through the wiring harness and look for issues, but I'd skip that and check the harness for damage where it leaves the body and enters the hatch. If no damage there, you'll need to check out the combination switch on the steering column--this will require an EWD and the ability to read it.

 

[MoustacheMike]

I had this issue a few years back...

Turns out it just needed to be re-grounded, as the old grounding point had failed.

Check on your grounds before looking at sinking money into a new motor assembly.

 

[ryanrtxtx]

I had this issue a few years back...

Turns out it just needed to be re-grounded, as the old grounding point had failed.

Check on your grounds before looking at sinking money into a new motor assembly.

Thanks! For a dummy like me, can you explain how I check the ground?

 

[MoustacheMike]

I'm not 100% sure to tell you the truth, I took my LX to the local dealership.

They identified the problem (faulty ground) and fixed it within a couple hours of dropping it off, I see to recall them charging me $40.

 

[n00g7]

Thanks! For a dummy like me, can you explain how I check the ground?

You need an electrical tester with continuity test. Find ground on component, find bare metal on chassis/frame (obviously not on the tailgate itself) and put leads across them. If it beeps, there's ground. You can also measure the resistance between the two, it should be very small, sub 1ohm. If it's larger, it's likely connection terminals are corroded.

 

[n00g7]

If you're in Austin area I'll do it for you.

 

[ryanrtxtx]

If you're in Austin area I'll do it for you.

Thanks so much n00g7! Wish I was close by... Going to try and figure it out tomorrow.

 

[SmokingRocks]

Does your brake light LED bar light up when you brake?

 

[SmokingRocks]

There is a connector behind the plastic panel on the hatch (driver side). This connector has the ground for the 3rd brake light and wiper motor run through it. My connector was nasty looking, like the terminals had corroded, I replaced the connector with some anderson powerpoles and everything worked just fine after that.

 

[ryanrtxtx]

There is a connector behind the plastic panel on the hatch (driver side). This connector has the ground for the 3rd brake light and wiper motor run through it. My connector was nasty looking, like the terminals had corroded, I replaced the connector with some anderson powerpoles and everything worked just fine after that.

My brake light works. If the brake light works does this mean my wiper issue isn't because of a bad ground?

 

[SmokingRocks]

No I'd still check that connector it's easy to get to

 

[interactivebagel]

I had to replace the relay. Here's my link
Rear Wiper Relay Fix

 

[MoustacheMike]

My brake light works. If the brake light works does this mean my wiper issue isn't because of a bad ground?

Nope...

Back when my wiper wasn't working, the rear brake light worked just fine

 

[fj40ingkc]

So I replaced the relay, and wiper motor, new switch on relay board, still getting the same issue. It worked briefly. But now is not working.

1. How to check new motor for maybe a short given there are 4 pins it doesn’t seem to work like a normal on/off with voltage.
2. Checked connector to motor under intermittent wiper and continuous wiper. There are two pins that rear at 6.7 Volts and another on intermittent mode that reads 4.9v and one is ground

Two old wiper motors, one original and one from junk yard have continuity on two of the pins where the new from Toyota motor does not.

Grounds are good, checking continuity between bolted in new motor and the body bolt for rear hatch piston to rear pillar on body beeps normal. 3rd brake light lights up fine. All wiring connectors in rear hatch are checked and greased with electrical grease and had no corrosion to begin with.

Any insight on voltage to rear wiper motor would be helpful thank you!

Update: I checked the ground, which was working, but not working very well, when grounding directly to the wire, white with black stripe that goes into the wiper motor grounded to the body, the voltage jumps up to 12 V which tells me the ground is weak. I re-grounded it to the body by passing the hinge, and the motor works fine. Likely just wasted a bunch of money on a new motor because I’ve only used once, but at least the wiper motor is working! Onward

Old switch is black on the left, new one from digikey on the right.