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

is the key light flashing with the key in?

 

Check the ECU-IG No 2 (7.5A) and ECU-ACC (7.5A) fuses in the interior fuse box for power on both sides with the key on.

 

Fuse is suspect. Did you say you put factory unit back in to test?

 

All fuses ok and OEM was reinstalled.
I checked all the little fuses in both places, those that can be pulled with the fuse grabber. Wasn’t sure how to check the large square fuses.

 

ECU-IG NO 2 Is 12+ and less than 1.
ECU-ACC is 12+ both sides

 

So ECU-IG No 2 is blown.

 

You may have to take the truck somewhere to have somebody that troubleshoots electrical issues go through it. Reason I asked about fuses is when I had my OTT tune installed, the installer spent some time troubleshooting my systems because he could not initially flash the factory computer due to communication errors he said were being caused by my after-market Sony head unit interfering with his laptop connected to the dash port. He pulled a fuse or two from under the hood that isolated the head unit circuit completely, and he was then able to factory update computer and install the OTT tune flash update. All worked fine on truck with Tune updates and Sony head unit without communication errors. This is why I knew about these fuses.

 

Meaning? (novice here)

 

It's bad, replace it with a new fuse of the same rating.

 

I don’t follow. I pulled the fuses and checked voltage on each side. The fuse wasn’t installed when checking voltage. Continuity on fuses is good.

 

No you need to check voltage on both sides of the fuses with them installed and the key on.

 

Interesting. I have the kdmax tune. But the no start remains with no radio, or either the OEM or Alpine.

 

How is that done? Where to put the multimeter probes?

 

Blade fuses have test points on them, put one of your probes to ground and the other to one of the test points of the fuse.

 

Wow, never knew that. Thanks.

All 4 test 12.5v

gotta run now, on the road until late afternoon. (Obviously not in taco)

 

I wired something to the inj fuse once and blew the fuse it would turn over but not start up. Key start. Look at all the under hood inj, efi fuses. Put a known good fuse in try and start it if it doesn’t swap that fuse back and do the same with the next. Try again.

 

Ok, when you get back to it go back and do the CAN voltage checks I listed in Post #17 and let's see where we sit there.

 

did you cut wires

 

Nothing cut.

 

What's the key light?