Weird electrical issue on 2015 Trail

[Biggcrisp]

Would be helpful if the OP could show us a picture of the power switch wire connections for the heated seats. We need to know if the radio shop down the street spliced into the wire harness or simply plugged that switch in.

I would like to think the BCM node could perform a self test after a power interruption and then relearn all of it's functions. Not sure if a Toyota does this or not.

 

[wfo9]

Would be helpful if the OP could show us a picture of the power switch wire connections for the heated seats. We need to know if the radio shop down the street spliced into the wire harness or simply plugged that switch in.

I would like to think the BCM node could perform a self test after a power interruption and then relearn all of it's functions. Not sure if a Toyota does this or not.

From what I read, it seemed it was all factory wiring and switches plugged in and there was no splicing.

The only reasons the seats are being blamed here is because it is something the customer changed after purchase.

It probably has nothing to do with the root problem, but it is something that naturally makes everyone think is at play. I'm hoping the dealer stands up and takes responsibility for diagnosing the real issue vs guessing. I know Toyota makes that hard for them to do and still make money.

 

[Biggcrisp]

Woah, As a tech-minded person myself, my first troubleshooting step would be to investigate anything that has changed recently; in this case the heated seats. However, now that I have basically ruled those out entirely (with the exception of the switches) I disconnected all the wires connecting the seats to the floor, and I'm still having problems.

Edit:
so I may take it by the installer this weekend and just ask them if there is any possibility their work is causing these problems. Maybe I'll even have them unhook the switches...

My internet opinion is...the switches could be incorrectly hacked into the wire harness. Lol

 

[BlackWorksInc]

My internet opinion is...the switches could be incorrectly hacked into the wire harness. Lol

If you look at his build thread linked in the first page of this thread he used Toyota Heated Seat switches. Everything was a simple plug and play matter, the shop shouldn't have had to hack anything at all besides adding a fuse to the fuse block and/or a pin in the fuse block if it didn't have it...
[MENTION=115178]Ezekiel2222[/MENTION]

Does your set-up use the factory 20amp Seat Heater Fuse? It should be located in the driver's cabin fuse block? The reason I ask is that I have seen some fuseblocks that seem not to have a compete pair of pins for some options (which seems stupid to me, but whatever.)

 

[Biggcrisp]

If you look at his build thread linked in the first page of this thread he used Toyota Heated Seat switches. Everything was a simple plug and play matter, the shop shouldn't have had to hack anything at all besides adding a fuse to the fuse block and/or a pin in the fuse block if it didn't have it...

[MENTION=115178]Ezekiel2222[/MENTION]

Does your set-up use the factory 20amp Seat Heater Fuse? It should be located in the driver's cabin fuse block? The reason I ask is that I have seen some fuseblocks that seem not to have a compete pair of pins for some options (which seems stupid to me, but whatever.)

You are correct! The OP stepped up and bought All wire harness required for a clean install.

 

[Biggcrisp]

If you look at his build thread linked in the first page of this thread he used Toyota Heated Seat switches. Everything was a simple plug and play matter, the shop shouldn't have had to hack anything at all besides adding a fuse to the fuse block and/or a pin in the fuse block if it didn't have it...

[MENTION=115178]Ezekiel2222[/MENTION]

Does your set-up use the factory 20amp Seat Heater Fuse? It should be located in the driver's cabin fuse block? The reason I ask is that I have seen some fuseblocks that seem not to have a compete pair of pins for some options (which seems stupid to me, but whatever.)

You are correct! The OP stepped up and bought All wire harness required for a clean install.

At this point it is up to the dealership to figure this one out.

 

[DougNuts]

You are correct! The OP stepped up and bought All wire harness required for a clean install.

At this point it is up to the dealership to figure this one out.

But until the OP steps up and verifies it was a clean install, those of us with experience solving problems are going to assume that something was hacked, loosely installed or accidentally damaged.

Unhooking the floor to seat connectors isn't going to solve the issue if there was something under the dash that was disturbed. If the electrical gremlins are contained to the body control module that runs the seat heaters, which were installed by some shop down the street, I would be auditing their work before I asked Toyota to diagnose.

 

[Ezekiel2222]

Luckily the dealer took the extra step of removing the wiring harness in the center console the last time I brought it in. Of course, that means I can't open the back window right now, but it also means ALL of the parts I bought have now been electrically disconnected from the vehicle.

The BCM is stock part which came with the vehicle; the audio shop did not install it, modify it, or mess with it in any way. As you say, it was a clean install.

I'm hoping the dealer gets some answers from the Toyota engineers today, because I'm getting tired of not being able to use my grossly overpriced seat heaters in the winter!

 

[Ezekiel2222]

So after hearing noting from the dealership for over a week, I called a talked to the service manager this morning. Amazingly enough he called back 10 minutes later with an "answer" from the Toyota engineers. According to him, they do not recommend installing a different BCM into my vehicle because it "might cause other problems". His recommendation was to replace the BCM with a matching one, and then he said I should get aftermarket heated seats...

I asked him if he asked the engineers why my heated seats worked fine for over a month, and he said he did not. He made up something about how the circuit could work but not be rated for the additional power draw, ect. I told him I wanted an answer from the engineers, at which point he told me there was nothing more they could do at the dealership and he gave me the number to the Toyota Customer Experience Center (aka corporate) and told me I could open a case there. I told him "sure, I'll make that phone call for you" and said goodbye.

Who would have thought installing official OEM Toyota parts into a vehicle requires a direct call to corporate headquarters! I must be super special or something...

 

[wfo9]

So after hearing noting from the dealership for over a week, I called a talked to the service manager this morning. Amazingly enough he called back 10 minutes later with an "answer" from the Toyota engineers. According to him, they do not recommend installing a different BCM into my vehicle because it "might cause other problems". His recommendation was to replace the BCM with a matching one, and then he said I should get aftermarket heated seats...

I asked him if he asked the engineers why my heated seats worked fine for over a month, and he said he did not. He made up something about how the circuit could work but not be rated for the additional power draw, ect. I told him I wanted an answer from the engineers, at which point he told me there was nothing more they could do at the dealership and he gave me the number to the Toyota Customer Experience Center (aka corporate) and told me I could open a case there. I told him "sure, I'll make that phone call for you" and said goodbye.

Who would have thought installing official OEM Toyota parts into a vehicle requires a direct call to corporate headquarters! I must be super special or something...

What a shitty customer experience. Where to go from here.

What happens if they replace the BCM with the matching part# (at your expense) and the problem is not resolved. Do they then take responsibility for diagnosing what the real issue is at that point? Do they not charge you at that point?

I would try go get some stuff in writing and complain as much as possible. Maybe even threaten a claim with your states attorney general... Don't be afraid to be a PITA. Sometimes that is the only way to get things resolved with these clowns. Maybe stand in the parking lot with a big sign on your truck stating "Ask me about my Toyota experience". I bet they will get it resolved at that point. Pick a busy day, like a Saturday....

I think the right thing for them to do is to replace your BCM and keep the seats out of the equation. If that fixes it, you pay. If that does not fix it, they keep digging until it is resolved (just like if you never had the seats installed in the first place)

 

[BlackWorksInc]

So after hearing noting from the dealership for over a week, I called a talked to the service manager this morning. Amazingly enough he called back 10 minutes later with an "answer" from the Toyota engineers. According to him, they do not recommend installing a different BCM into my vehicle because it "might cause other problems". His recommendation was to replace the BCM with a matching one, and then he said I should get aftermarket heated seats...

I asked him if he asked the engineers why my heated seats worked fine for over a month, and he said he did not. He made up something about how the circuit could work but not be rated for the additional power draw, ect. I told him I wanted an answer from the engineers, at which point he told me there was nothing more they could do at the dealership and he gave me the number to the Toyota Customer Experience Center (aka corporate) and told me I could open a case there. I told him "sure, I'll make that phone call for you" and said goodbye.

Who would have thought installing official OEM Toyota parts into a vehicle requires a direct call to corporate headquarters! I must be super special or something...

I find that answer to be sub-par at best. We already established that everything was factory (you still didn't answer me if the power source for the seats is the actual Seat Heater Fuse in the fuse block under the dashboard as this is the only variable that we haven't accounted for yet) and that the BCM module has nothing to do with seat heater operation and that both modules pull power from the network for module operation and from a separate power line for actual duty current.

 

[Ezekiel2222]

I'd love to verify what the power source is, but I don't really know where/how to look.

I called the Customer Experience Center, told them my whole story, and started a case. Now I have to wait for a call back from my case manager (by Tuesday) to continue the process.

 

[Saker]

I'd love to verify what the power source is, but I don't really know where/how to look.

Here is what and where to look for your power source to the left of your steering column under the dash!

[MENTION=115178]Ezekiel2222[/MENTION]

Does your set-up use the factory 20amp Seat Heater Fuse? It should be located in the driver's cabin fuse block?

 

[Ezekiel2222]

Well I think I found the fuse block you were referring too. According to the cover, there is a 20A "S/HTR FR". Of course there is also a 30A "P/SEAT FR" and a 30A "P/SEAT FL". I also find it interesting that I have a 25A "S/ROOF" even though my vehicle doesn't have a sun roof.



Anyway, as you can see by the pic, the 20A "S/HTR FR" fuse is present. I'm not sure if that means it's being used or not, but hopefully it answers your question.

The whole "Customer Experience Center" thing has taken me in a circle right back to the dealership. Supposedly some regional rep will be in the area next week who might be able to offer me some answers.

 

[gm350reratliff]

One way to check would be to reconnect the seat heaters, turn them on, use a volt meter to watch voltage at the connectors, then pull the fuse(s).

 

[Ezekiel2222]

Unfortunately like I mentioned above, the dealer removed the control modules from the bottom of both seats, and also removed the entire switch wiring harness from inside the center console. I have all the parts, I'm just not sure how feasible it is for me to put them back in right now.

I'd love to hear back from BlackWorksInc and see if this answers his last remaining question.

 

[Ezekiel2222]

So I went back to the dealership on Friday to meet with the Field Service Technician who came down from Denver. We sat down with the service manager, and started discussing the problem. Naturally the service manager kept referring to how "the BCM is fried" and "the heated seats caused it", and I kept reminding them that we didn't know if either of those things were true yet. They also tried to shift the blame to the auto-sound place, again without knowing for a fact what the problem is.

After about 15 minutes of doing my best to be respectful but firm in my point of view, I provided them a copy of BlackWorksInc's post, along with the wiring diagram. I did not include his username or the forum name, but I did point out that he was an ACE Certified Master Auto Technician for Toyota. They both read it over, stumbled for a minute trying to explain it away, and then decided they should get on the computer and print out the diagrams themselves, which they had clearly not looked at up to this point! The printed out the same one I gave them, along with a "power source" diagram, and a "ground" diagram. The service manager was sure he had found the culprit when he looked at the ground diagram, because "the heated seats and the BCM share a common ground"...

We wrapped up the discussion in the office with my displeasure in the fact that Toyota doesn't allow customers to customize their vehicles before purchase, and they certainly don't allow it after purchase either. The FST said he would do some more research to make sure that putting the BCM from a Limited into my Trail would work, but they both made sure to point out that they couldn't cover it if it stops working in a few months because it's not "stock".

Finally I took the FST out to the vehicle to show him the problem first hand. While we were out there I explained to him that ever since I told the dealership I had installed aftermarket parts, their attitude was one of "blame the customer." I asked him if it was Toyota policy to always blame the customer? I also asked him what the dealership would have done if I hadn't been so honest and said "nope, it's all stock"? Would they have continued to diagnose and find the real problem? Would they have found the same problem, or a different one? Lastly I pointed out that I know how warrantees work, and until the dealership can prove conclusively that the BCM is bad, and that the heated seats caused it, I am still covered.

I'm not sure if any forward progress was made, but at least we didn't go backwards either. Waiting for a call back from the FST via the dealership sometime next week.

 

[Biggcrisp]

My time is money and computers are disposable. Your dealer is acting like a BCM is a mystical treasure that he has no access to.

The moral of the story is: tell a dealer the fault conditions and nothing else. Never should have admitted any hint of being at fault.

Write or wrong this is the way the world. If you believe you are at fault here, then pay up and move on. If you don't then stick to your guns, but remember not to admit any fault the next time.

 

[BlackWorksInc]

Back feeding from the ground could be a possible explanation; but that is something that is most likely not caused by the seat heaters directly as many of those grounds go into junction blocks and then into the body itself. For the back feeding to occur that would mean there is an issue where all the grounds feed into a junction block which is all factory wiring that wouldn't have been disturbed by your plug & play seat heater that uses existing wiring. If there was an issue with the junction block and/or final connection it could allow excessive voltage to try and find a new ground through other sources (such as the BCM or other components), but that is a pretty rare occurrence

Post Note-

Looking at the "Ground Point" diagram I don't see the connection made between the Main Body ECU and the Seat Heater system. Both Seat Heater Controls & ECUs are located on Ground branches that terminate into final ground connections O1, O2, N1, and N2. While the Main Body ECU has 2 ground wires that are part of a large branch that terminates into final ground connections F1, F3, I1, and H1; so for the idea that voltage is back feeding up the ground path into the Main Body ECU from the Seat Heaters means it is using the actual body of the vehicle as an electrical path; thus implying that there is a more significant over all ground issue between the body of the vehicle and the negative battery terminal (which to me seems very unlikely as such a large ground issue would present with other symptoms.) I feel like that theory is stretching too far to try and tie your seat heaters as part of the BCM failure.

 

[gm350reratliff]

:snacker: