Major electrical issues

Ok so here it is the key fob quit unlocking/ locking the doors, changed battery still doesn’t work, interior lights only come on with accessories on, windows quit rolling up/down, AC only blows out defroster, none of the lock/unlock features on door handle work, alarm will not go off at anytime or with use of the panic button, trip mileage and fuel economy reset to 0 every time you shut truck off, lost all stored contacts for phone list in radio along with all previous destinations addresses and such the only thing that was there was programmed radio/XM stations. Took truck to dealership to fix and for $800 the took out part of the alarm hot wired the front windows to work even with the ignition turned off and the doors opened, but the FOB still doesn’t work and was told it was the rear view mirror and for $900 plus they could order and install it. Ok I may not be the greatest mechanic in the world but I can read wiring diagrams and do know how to search the web (my favorite place to ask car questions and get answers for free is 2carpros.com) I sent these guys a question explaining everything as I have here and in less than 24 hours had my answer, the body control module with explanations and all of the needed wiring diagrams. So even after the dealership having the truck for 5 days the first time I was a little pissed and took it dark to them and demanded that the fix it right and it was their Bill to do so. I questioned them on the mirror verdict and how they came to that conclusion, they said when they unplugged it it quit blowing the fuse, but I had already made sure all of the fuses were good twice. I asked if they even checked the BCM and suggested that they do so. Well they have now had the truck another 2 days and it’s still not fixed and they say they don’t know what’s up or can’t find the problem with it. Has anybody else had a BCM go out or any other weird electrical issues.

 

Doooood. Paragraphs really help.


There was a guy with a burned through BCM recently. The dealer tried to blame an aftermarket stereo installation, but where the hidden damage was, there was no way it could have been the radio. This was easily seen once the BCM was removed.

I'm not saying that it is your problem, but swapping in a new one may be the thing. Tell them to pull one from a Taco on their lot.

 

You would think they might just have one in stock on their shelf. I’m sure it’s the BCM and they should have a computer that they can plug into the OBD plug that will tell them if the problem is there, but they won’t listen to us people who are not Toyota certified mechanics because what do we know. This is California. But thanks for the help.

 

Electrical pixies are finicky bitches. It takes someone with pride in their work and brains to do their due Diligence and track down the exact problem (broken / shorted wire, BCM, etc). It's not surprising the dealer wants to shotgun parts. They're lazy and feel like you need them, scumbags.

 

Do what they did and unplug the mirror. See if it fixes the issue. If it's does. It's a free fix, with blinded eyes at night. Better than another $900...

 

The toyo dealers are f-ing dummies.

 

Normally they probably would, but that chip shortage is no joke.

 

Any electrical mods?

 

Mechanics no longer work at dealers, they all retired.... Now all we have are parts replacers that cant diagnose and just throw parts till the problem goes away. After all, its not their money they are wasting.

 

Fuckin bums me out. But unfortunately you're right. Make me appreciate my upbringing even more. I can bypass these hacks and do it myself.

 

Same here, I grew up before cell phones... your car breaks down your either fixing it on the side of the road or walking home.

 

Luckily I grew up curious! Haha.

 

The days of being able to fix it yourself on the side of the road are long gone with new vehicles. This isn't grand pappys square body with a 350 SB.

I suppose if one wanted to pack a bi directional scan tool and a bunch of parts they could fix it on the side of the road. Don't forget you're going to need more than a set of water pump pilers, a 9/16, 1/2 wrench and a multi bit screwdriver.

 

No none at all

 

I can understand that one

 

We plugged the mirror back in that they left unplugged and never blew a fuse one, but didn’t fix the problem

 

There’s no magic scanner to automatically tell you an exact electrical problem, the cause and everything that is defective due to the failure(s). A short in a rear view mirror could very well take out a body control module.

 

Ok so I just talked to the dealership and they still can’t find the problem, told them to put it back together I will be there in the morning to pick it up and I’m going to take it to someone who can fix my problem, they said that they changed the under the hood junction box, the BCM, and they were now checking the window motors, but what’s funny is all of the windows roll up/ down just fine except when ignition is off only the front ones work. Oh and they said that the truck won’t go into accessory mode?

 

I’ve learned that in my investigations and they said that they changed it and it didn’t fix the issue. I believe in the owners manual is where I read that the dealership can hook up their code reader to the OBD port and it will tell them if something in the BCM is malfunctioning.

 

You can pull codes from a BCM. Some can tell you there is a short, or open circuit. If the BCM is bad it can throw many codes. There isn’t a bad BCM code. Following diagnostic procedures you search each fault code and there is a flow chart to trace the issue. If the BCM is bad it can throw many codes, which aren’t related to a fault or failure of the BCM in itself. So trouble shooting takes time. As for replacement it has to get approved by Toyota. Toyota doesn’t want a tech to just replace a BCM. So they have to follow the flow charts and get on the phone with tech support. Usually it’ll be a engineer who will tell them to replace the BCM. As for the part itself, there are many different BCM’s they are different in all models and trims. So dealers usually don’t stock them. They get them in a couple days from their parts suppliers.