Open wires in clutch switch circuit, HELP!!

Hello,
I was away for work for a couple months over the summer, when I returned my manual 2021 Tacoma wouldn't start. After some troubleshooting I discovered the clutch switch circuit is open (therefore now only starts when the 'Clutch Start Cancel' is engaged). The switch was bench tested and works perfectly, I also made a jumper wire to bypass the clutch switch and it still wouldn't work. I later discovered the blind spot indicators in the mirrors also no longer work. It seems as if a rodent nested in the truck while I was gone and chewed some wires. I brought the truck to a shop to have them fix it, and after a week they came to the same conclusion as me and told me to bring it to the Toyota dealership as they should be able to fix it. I don't really want to go that route as I've already paid hundreds to have this fixed and all that needs to be done is a bit of soldering. If anyone has any ideas please let me know, I'm unsure if the clutch switch and blind spot indicators share a ground? All I could find from a couple schematics was that the clutch switch goes to the Engine Control Module. Any help/suggestions is appreciated.
Thanks,
Zac

 

A few posts in here might help..

https://www.tacomaworld.com/threads/what-did-i-do-to-my-clutch-start-cancel-switch.416573/

edit: also might be helpful, few schematics here too
https://www.tacomaworld.com/threads...p-rewiring-clutch-start-cancel-switch.689000/

@TnShooter @Dm93 might be able to help if they are willing

 

I did look into it.
I can help more later tonight.
I'm busy right now. And honestly don't have the time to look up connector pinouts in order to make diagnosing easier.
Plus anything after 2015 is a bit of a "process" for me to gather. As the service info I have is less than convenient to navigate.

I'll throw something together later tonight. We can at least trace it back to what connector doesn't have the control for the STA relay.
It's likely not a ground, not if the truck starts with the cancel switch. It's pretty much got to be the relay control.

 

I don't have time to look up locations right now but here's the wiring diagrams.

I have to ask are you sure your on the Clutch Start Switch and no the Cruise Clutch Switch? The Clutch Start Switch is the one that is depressed when the clutch is fully depressed, the Cruise Clutch Switch is depressed when the clutch is fully released.

 

Ok, I took a look at the diagrams and have a place to start.
First make sure you are testing the correct switch.
The Clutch Switch has a Light Brown and Yellow wire going to it.

Unplug the Clutch switch and see if the Light Brown wire has power to it when cranking.
I betting it doesn't, as the truck doesn't start. But we need to be thorough in the process.

If we have No power we need to move onto the IS4 plug. And we'll need @Dm93 to get us the location.
My data is limited, I have diagrams, but not locations. A very few connector pinouts.

On the IS4 we need to check pin 15. It's the same light brown wire that goes to the Clutch Switch.
See if it has power when cranking.
If we have power, the break is between the plug and the clutch switch.
If not, is further up the line. So next we go to J13 Pin #15.
Again, check for power when cranking.
If power, the break is between J13 and IS4.
If not, check pin #14 of the same plug (J13) a purple wire for power when cranking.

Surely we will have found it by then. As the next stop is the physical ignition switch. Highly doubt that is the issue.

Now.....Let me dig up some connector pinouts and maybe locations.
But I'm betting we'll need @Dm93 for those.

But I'll see what I can come up with.

 

Clutch switch.


IS4

J13

 

IS4 is inside the cab and is where the instrument panel harness hands off to the engine harness. Considering that what is common between the clutch circuit and BSM is that they both run through IS4, I'm going to assume the issue is on the engine harness under the hood. Probably somewhere around the big fat bundle that is taped up to the bracket that bolts to the firewall. You probably already know where the actual damage is though...

The BSM and clutch start circuit both run in the engine harness from the firewall, around the back of the engine and up the left side of it, and dump into the relay box on the left side. Clutch circuit goes through EA1 to get into the box, BSM goes into the box through EB1. The "body" harness portion that runs down the frame to feed the BSM rear sensors picks up from the relay box in a different connector.

None of that last paragraph is too relevant to your actual problem except to say that the only commonality I see between those two circuits is they both exist in the engine harness between IS4 and EB1/EA1, and a rodent probably chewed through that portion of harness and knocked them both out at once. The two systems don't appear to share any actual circuitry at all so it's unlikely either is affecting the other, aside from a rat that got to both of them. Especially since you know for sure you have an open on the clutch switch circuit itself, which has nothing to do with the BSM that I can see.