Help I fried my taillights!! 3rd gen taco

Ok So lets start from the begging, A couple months ago I upgraded my rear bumper to a high clearance bumper and while i was installing it I accidentally cut a small green wire from the towing harness in my attempt to make it reach. I then noticed one of my rear tail lights wouldn't turn on, the top left. I ignored it and thought I knew it was because of that small green wire and I would eventually get down there and fix it. fast forward two months later and I bought new taillights on tacomabeast. After Installing i noticed i kept blowing the 7.5 amp fuse labeled tail. I mistakingly grabbed the wrong amp fuse and used a 30amp to replace it. I smelled burnt wire inside my cabin by the driver side and turned the lights off and found my dumbass mistake. after I removed it and replaced it with the right size the lights would no longer work. I left the stock tail lights on and put the tacombeast lights away. now here is what I know so far.

Brake lights work.
blinkers work.
reverse lights work.
the lights that flash when you press the remote work.
bulbs are all working.
that 7.5amp fuse has current flowing through it still.

The following does not work...
taillights, license plate light, front amber parking lights.

I found a wiring diagram (attached( and notice this is all limited to the same circuit. My question is for anyone that is good with diagrams. following the path of the current after placing that 30amp fuse, what did I fry?
where do you suggest i look?

and yes i know, that was a dumbass way to mess up.

 

If you have not fixed the green wire that you cut a couple months ago get that patched up first.
For the wiring where the 30 amp fuse was installed start at the fuse box and look for where the wiring branches out towards the circuits which failed based on the wire colors in the diagram. It’s going to be a PITA tracing it back to where the wiring burned. Good luck getting this figured out.

 

wow. yeah you burnt a wire somewhere. luckily it didn't catch fire.

 

You might get lucky you smelled the melting wires in the cab .

could be melted relays from the over current condition

Might be around the fuse block might be under the door scuff plate.

Then you still have your short it might be the green tail light wire you cut if the bare wire is exposed then it might be else where .

depending how much damage was done a used tail light harness might be a good idea .

best of luck

 

Start at the cut wire and work backwards from there towards the fuse panel. You way have to run a new green wire.

If you were melting wire insulation it should not be hard to find.

On a brighter note the actual tail lights should be fine as all the current was shorted to ground before it reached the tail lights.

 

Now that you have the right size of fuse back in it, does it burn the fuse when you switch the tail lights on? Or does it do nothing at all? If it burns the fuse, then you may be lucky and have reverted to the same state where you kept blowing the 7.5 amp fuse. If it does nothing at all, it means that you killed something and need to find and repair it.

So assuming that you killed something and its not blowing the fuse any more, and since the damage would have been done while you had a way-too-big of a fuse in there, the damage could be either before the fuse, OR AFTER.

So first thing you do, is check with a voltmeter if there is still power at your 7.5A Tail fuse *when the tail lights are switched on*. If not, then you need to work from there back towards the box under the hood. You do not need the fuse to be installed for this part, just connect one lead of your voltmeter into the fuse socket, and the other to the chassis.

For back towards the box under the hood;
1) locate the TAIL RELAY. Check if you have power running to it. If not, then you toasted the wire that runs from the "J/B-ALT" fuse to the TAIL Relay.
2) check that the TAIL Relay is actually switching when you switch on the tail lights. You should hear a faint click, and you need to actually measure voltage coming out of the relay that wasn't there when it was off -- sometimes relays can click but still not conduct.
3) If the relay is working, but power isn't making it to the 7.5A fuse, then the wire from the relay to the fuse is toasted.

And that covers everything from the battery to the 7.5 amp fuse.

If you find that power *is* available on the 7.5 amp fuse, it means that you need to trace it forward (in terms of the circuit, not in terms of the front of the truck) to the tail light.

Take a look at the second page of your circuit diagram. You can see that after the tail fuse, there is a junction labeled "1F", and a GREEN wire running out of it. That green wire connects to a bunch of stuff, including several connections to the headlight assemblies. If none of those lights work at all, and you have power at the fuse, and the fuse is good, then the damage *must* be between the fuse and that point where the green wire is connected up with all the other wires there (P for pink, V for violet, Y for yellow, L for light blue, and another G for green). So replace that wire and disconnect the EB1 connector and verify that the parking lights are working again.

Once you have the parking lights working again, then you can go back to the back and get that green wire you previously broke straightened out.

 

thank you for the time you took to type all that. I will give this a try tomorrow and report back to you. really appreciate it. How likely is it that the ECU fried something? or would it be a wire that got fried leading to the ECU? seems like the relay clicks on, but i haven't tested voltage to it. and there is definitely still power to the 7.5 which has stopped blowing.

 

SUCCESS!! So after I read 96cardboard response on here I got to really understanding what those diagrams meant. I was able to pull up the Toyota service manual and traced the issue forward like you said. turns out I fried my junction block. if you look at the diagram there are some fuses and relays inside it that you can not replace and you HAVE to replace the whole junction block. I ran power to that green wire to confirm my findings and everything worked. now i just wait for the new junction block to come in. this is how much i saved.

Toyota dealership wanted $608 just to diagnose. junction block with them was $266. and im sure they would have added an extra hour of "labor" to instal it ($120). so $994 before tax.

Found the oem part online for $177+tax. Thank you all that took the time to help out.

 

Would you mind providing info on the junction block/a link. And also maybe a description of how to replace it?
I'm struggling.

 

Let me look real quick. Also it’s two 10mm screws and the box has like 3 wire looms that connect at the rear. Once you remove the screws you can get a better look at the rear.

 

https://www.ebay.com/itm/2016-2017-...IVER-S-BOX-JUNCTION-82730-04061-/174555845825

 

thanks!