Posted on Rising Sun Forum as well - Non Working Rear Wiper/Defroster lead to Fire?? (2 Viewers)

[NewbyColorado]

I have a 1997 80 series, 298K but 98K on a Robbie rebuilt motor. I take pretty good care of it even those I am a .5 banana mechanic. My rear wiper and my rear defrost have stopped working. In the rubber housing that goes from the head liner through the rear gate, I can move it around and see that the rear dome light (which has an LED panel) can go on an off. So, I was thinking there was some wire that maybe damaged. But, since I am not really good at this, I put the panel on the rear hatch again. I reached out to someone who was an electrical specialist and he just left.

Basically, he told me not to drive the car. That the computer is corrupted and my ground is now hot. The computer is confused by what is hot and what is not and that if I keep driving it, eventually the computers will crap out and begin to shut down. The price to redo the computers and fix the ground for the rear hatch would be $2200. If I kept driving it, it would eventually catch on fire.

I just did 500 miles last week with two trips to the mountains and other than the rear defrost and wiper not working, the truck drove great. I just tried the rear wiper and I could hear the relay switching but the wiper doesn't move.

Is it possible that this is the start of something catastrophic? I have a 12v socket that goes to the back of the vehicle that I run my fridge off of and still works just fine. I am going to take it to someone else now for a second opinion. With the knowledge here, just wondering if anyone has ever heard of something like this happening or is possible?

No codes, no odors, rear dome light works, the rear wiper fluid works, just not the wiper/defrost...

Is this possible? and should I NOT drive the vehicle. Right now the battery is disconnected.

Thoughts please?

 

[leonard_nemoy]

Definitely take it to another mechanic for a 2nd opinion.......

If someone told me "That the computer is corrupted and my ground is now hot. The computer is confused by what is hot and what is not and that if I keep driving it, eventually the computers will crap out and begin to shut down." Than I would run away and find someone else.

 

[NewbyColorado]

Thanks! I am definitely going to get a second opinion. Earlier today, I would have driven right back to the mountains and not thought twice about it, but now I'm not sure if I should drive it till my appointment.

 

[BILT4ME]

Thanks! I am definitely going to get a second opinion. Earlier today, I would have driven right back to the mountains and not thought twice about it, but now I'm not sure if I should drive it till my appointment.

Also, Toyota does not do everything the same as Domestic vehicles.

Toyota switches the GROUND side of the circuit.
Domestic switches the HOT side of the circuit.

With Toyota, if there is an inadvertent ground, the item will power up (such as a dome light) whereas in a domestic vehicle, if it inadvertently grounds, the light will not work because there is no power feeding to it.

Get a different electrical mechanic.

 

[NewbyColorado]

Thank you! I am going to get a different electrical mechanic.

 

[jpoole]

Shorts in the copper wires inside the rubber tube from body to rear hatch are fairly common.

After not having full rear-wiper functionality for a year or so I was able to repair shorted wires in that section of wiring without much surgery. Rough memory says that I dropped the headliner a few inches in the rear quarter to unplug a few things and get some slack. I then was able to squish the rubber boot down and access the wires that needed repairs, sort them out and then put it all back.

That's not an attempt to give you a thorough guide as I have no idea if you are even interested in fixing this yourself but if you have any experience with fixing broken wires then you should consider doing some inspection and repair of the wires that are in the rubber tube and then re-evaluate. Decent chance you'll resolve all issues by doing this and won't need additional opinions/etc.

If you find someone to help with this keep in mind the general ideas above and that someone competent should be able to fix those wires or similar issues in that area pretty easily and you may have no remaining issues beyond that.

 

[Malleus]

I concur with everything that's been said about your "electrical specialist". Based on your description, the only this he specializes in is taking a lot of money away from people. There's very little, if any, risk of fire and absolutely no risk of damage to "the computers", since the rear wiper and defroster aren't connected to any, in any way, other than being in the same truck.

If you're interested in seeing for yourself, download a copy of the Toyota repair manual (AKA FSM) for the 1997 model from the Resources section. The electrical wiring diagram (AKA EWD) is in there, too. Taken together, both documents completely describe the truck, how it works and what to do if it doesn't.

FWIW, there's no way to "redo" any computer in an 80 series Land Cruiser. They're not reprogrammable in any way.

 

[Malleus]

Purely for the sake of curiosity, what responses did you get from Rising Sun?

 

[NewbyColorado]

Thank you @Malleus. Very similar to what was written here "

" There’s a big relay in the back hatch that controls the wiper motor. You could unplug that if you were concerned. There are no computers in the circuit and a 20A wiper fuse to protect it. While I probably wouldn’t continue to try and use them, I would not hesitate to keep driving it. In my opinion.


The defroster and wiper motor are independent circuits that use the similar grounds (locationally). It’s possible that the ground has gotten corroded or something."

"The risk of frying the ECU is basically slim to none.

Strictly speaking there is a small risk of a fire or hurting a relay if a wire is exposed or insulation cracked. I don't mean to imply it's a ticking time bomb as long as the factory wiring hasn't been tinkered with, the fuses *should* do their job.

Pulling fuses will make it slim to none."

These two quotes are from really knowledgeable guys as well.

 

[Mark W]

I've got nothing to add to the complete and accurate comments you have already gotten. Except... DAMN!!! Where did you find that "electrical specialist"??? Does he actually get paid for this sort of... knowledge? It sounds to me like he is a specialist in scaring soccer moms into getting expensive panic driven "work" done so that he can pay for his boat!

Mark...

 

[simple]

He isn't dumb. He knows anyone who drives an 80 series from Denver up to the mountains twice in a week has some money to burn. The gas stations will start offering you little gifts soon also.

 

[LandLocked93]

+1 - the fuses will do their job.
+1 - the ECU might as well be an orbital dynamics mainframe sitting in Cheyenne Mnt during a high-altitude nuke test.
+1 - the other guy isn't dumb, but maybe not familiar with ground-switched circuits if all he works on is hi-side switched stuff.

Were I still in CO I'd be happy to help. It's really just starting at the wiper motor (disregard the defrost for now) and trace back till you find power.

There is ToyoTech in Colorado Springs that could proabably get it handled fairly quickly. Tho they are busy usually. Give'em a call.

 

[Malleus]

Here's a sample from the EWD:

Take special note of the annotated ground point at the bottom of page 34. This is a sheetmetal screw. Make sure it, and the wire termination connected to it, are clean and the hole it goes into is also free of rust.

 

[jpoole]

The additional troubleshooting help may end up being helpful but there appears to be a shorted wire between rear roof area and rear hatch:

In the rubber housing that goes from the head liner through the rear gate, I can move it around and see that the rear dome light (which has an LED panel) can go on an off.

At their current age and with much hatch use this is common for 80s and should be fixed as the next step since it may be all that's wrong. If issues remain after dealing with the shorting wires then all of the extra info will come to bear I'm sure.

 

[NewbyColorado]

Thank you guys!!! @Malleus - I had printed those pages out for him, just in case he needed to see something. He didn't look at it.

 

[NewbyColorado]

He isn't dumb. He knows anyone who drives an 80 series from Denver up to the mountains twice in a week has some money to burn. The gas stations will start offering you little gifts soon also.

I definitely needed the gas station help last weekend!! Good thing there is some downhill!!

 

[NewbyColorado]

I've got nothing to add to the complete and accurate comments you have already gotten. Except... DAMN!!! Where did you find that "electrical specialist"??? Does he actually get paid for this sort of... knowledge? It sounds to me like he is a specialist in scaring soccer moms into getting expensive panic driven "work" done so that he can pay for his boat!

Mark...

Recommended to me by a "friend"... No Christmas card for him now!!

 

[LandLocked93]

@Malleus I had printed those pages out for him ... He didn't look at it.

There's a flag.

 

[jonheld]

That the computer is corrupted and my ground is now hot. The computer is confused by what is hot and what is not and that if I keep driving it, eventually the computers will crap out and begin to shut down. The price to redo the computers and fix the ground for the rear hatch would be $2200. If I kept driving it, it would eventually catch on fire.

This guy sounds like a moron to me. He/she/it has no idea what he/she/it is talking about.
At the very least, he doesn't want to work on your truck.
If "ground is now hot" and your "computer is corrupted" then please tell me how the engine is running. Not possible unless we change the laws of physics.

 

[NewbyColorado]

Thank you Jon!!! With the advice from this forum, I was able to sleep and not feel like I have decide between getting it fixed and a new vehicle!! His scare tactics works, but I also knew I should double check with y'all. Lesson learned...