Truck won't start after head unit replacement. *** solved ***

Meter Fuse is the DASH lights.

To confirm. You put the black probe on a body ground, and the red probe to each side of the fuse?
Correct?

If so, we have power failure TO the fuse.

We shall then move on to checking the IG2 Main fuse (20A)
And the AM2 No.1 Fuse (30A)

Check them the same as you did the Meter fuse.
That is if you check the fuse correctly, as I described above.

 

So we seem to be missing a power feed, have to go to the fuse(s) upstream.

Toyota refers to the instrument cluster as the Combination Meter, the METER Fuse provides ignition power to it.

 

I have about 30 mins before I have to leave the house.
If I can't get back to you. The diagram below should be of help (or at least to Dm93). I will get back to you. I promise, but It's will a couple hours.
I think we are 75% of the way to solving this now.

 

Again, check the following fuses.

IG2 Main fuse (20A) - Should be 12v
AM2 No.1 Fuse (30A) - Should be 12v

 

Key needs to be on when checking the fuses just to be clear.

 

IG2 is 12.2v on both sides.

AM2 #1 is a 30a square one, looks ok? How are they checked?

AM2 #2 is 12.2v both sides.

 

Usually you can look through the "glass" and see it blown
Compare it to the one above it. It should be the same type fuse (for the radio)

You have 2 options to check it.
Replace the fuse with a known good, and hope like hell it doesn't blow it immediately. (if it blows, you have a short) Those fuse are expensive, like $5.00 each.

Or pull the IG2 Main RELAY and test the terminal.

@Dm93 will have to take over from here. I have to leave the house for a bit.
Dm93, we'll need a fuse box pinout if we go the relay route.

 

Checked all 3 ECU-B fuses 10A. No1, 2, 3 ?

 

It looks good, I pulled it and another 30a square one and both have continuity.
How can voltage be checked? Pull it and check each post?

 

ALL blade fuses have been checked for continuity, in both locations.

 

Sure am glad I also have a working 2000 Sienna.

 

so when you test the fuses you are using a test light and testing both sides on top of the fuse?

 

It seems you took down CAN. Either via short in Main Body ECU or some modules are offline.

Recheck ECU-B fuses. Use a good known one. Are you sure it did not accidently unplug any connectors behind the radio that does not belong to the radio? There are some junction connectors for CAN.

Also these

 

Been pulling them and checking continuity.
I suppose the test light will show power at the fuse.

 

Does your fuse box under the hood look like mine or is anything different? I would take the negative off the battery and start checking relays for a burnt spot .

 

takes forever that way and more risk of mistakes

 

all 3 ECU-B fuses check ok, continuity and light probe. Don’t see any connection issues behind radio.

 

looks the same.
How are relays tested?

 

Dm93, TnShooter, RIXTUX and Vlady:

You guys are awesome for all the time you're spending on this.

Hope you find the answer.

Sorry if I missed anyone else.

 

https://youtu.be/ieyr63wDqG0?si=0Z1U5jsU3mvYt1VR