Water Leak causing Wiring Harness Issues

Hey y'all,

I had an interesting issue pop up with the Bullrunner yesterday and was curious if any of you have experienced something similar or have any advice.

After it was parked in my driveway all night, I started it yesterday morning and drove about 20 seconds before the engine cut off, dashlights turned on, and the info screen stated "high transmission fluid temperature". I turned it off, tried to turn it back on, it turned over but wouldn't start.

I had it towed to the Toyota dealership and they're saying that the issue came from water damage to the wiring harnesses from a sunroof drain clog/leak. They also said there's no issues with the transmission. The fix according to them is to replace all the wire harnesses. They haven't sent the quote yet but said it will be several thousand.

I'm wondering if any of y'all have experienced this and if it's possible to have a different shop identify/replace the specific wire causing the issue and replace it, rather than the entire harness. Any help is appreciated!

 

Never had an issue with the hardness but I can confirm when the engine shut off on its own you get the trans warning and dash like a Christmas tree. So I'd take their word the trans is fine.

I ran out of gas in the Tacoma because my float was bad (told me I had 1/4 tank) and I got all those symptoms.

 

Electricity doesn't like water. But most modern insulation is thermoplastic so it's water tight. Have you dried everything out? I can understand water issues at connection points. But I'm skeptical about the harness being damaged because it got wet.

Take it to an automotive electrical shop and see what they say. You might find out the dealer is taking you for a ride...

 

An automotive electrical harness is not watertight. All of the terminals are crimped / staked on after the wire end insulation is stripped back. Water can get into the harness at these points - and there are a lot of them - and literally run right down the inside of a wire. Given a little time, this will cause corrosion and you know what happens next. In an environment where road salt is involved, this can get really bad, really quickly. (I know that from personal experience.)

 

Yes, this just happened to me. Maybe I should just know that there are sunroof drains, but there is no mention of them in the owners manual and no mention of keeping them clear. They clogged and the water shorted the electrical system and I had all sorts of safety alerts going off. Take it to the dealer and they replaced wheel speed sensors, not knowing there was water causing the issue. Driving kids to camp, on the highway, it shorts again with all of the warnings and loss of speedometer. Take it back to the dealer. They found that so much water collected under the floor board that "organic matter" aka mold had grown and they are quoting me $8-10K for remediation. I never noticed any water or wet carpet. Who designs an unsealed drain tube to run down next to electrical components? I'm not going to let this one go. Toyota has had recalls for other models due to water leaks, but the dealer says there has never been an issue with 4Runners. Well, there's an issue now. Has anyone ever gotten any resolution from Toyota on an issue like this with a 4Runner?

 

Hi - did you ever resolve this issue...What caused it?
My 2017 was parked after a long drive for 3 days near a lake. Third day we had a monsoon like rain with winds blowing toward it. In the morning I went to move the 4Runner, it clicked did not start and I got that high transmission fluid temp message flash. Tried starting again and it started briefly but as soon as the AC kicked in engine died. I charged up the battery and since then it cranks good but will not start.
Appreciate any suggestions.

 

Same thing with me on my 2014 4rnr limited. Sunroof drain got clogged which caused wiring dash harness to short .not sure if I should get the whole harness replaced from the dealer or shop around at other body shops.

dealer is quoting 6 k to replace

 

As an update on mine. I left the 4Runner at our cottage from this event. Next time up I went with my Tundra and my tools. Was hoping it would have dried out. Still no start.
With my testing light I went through every fuse. Both sides of the fuses. Slowly.
The ones in the Cab were ok. Went to the engine bay. All seemed ok then with 6 remaining to test one of them lit on one side but not the other. Hmmm Labelled - Fuel Injector Fuse.
Changed Fuse - 4Runner started. I left it there.
Pretty sure my AC drain tube is plugged and part of reason the floor was wet.
When I get it home will look at it.