DRL mirror switchbacks killed my truck

And the dash switches also?

 

Yes

 

Another dumb question - do the taillight bulbs test good?

 

Holy #$&?!!
Learn something new every day. Thanks.

 

Ok guys, so first off, thanks for so much effort and knowledge. Secondly, yes all the dash lights and whatnot dim or brighten accordingly.
@PhenixFord swapped the horn and tail relays, relay is good, but I'm not getting any reading out of the fuse body

 

Although in hindsight, the multimeter I have has relatively larger prongs and I can't guarantee I was making a good connection mashed onto my back under the steering wheel there... I'm like 90% sure tho

 

Mikeyd.25 I actually haven't checked those yet, since when these lights last tripped there was a definite smell of electrical in the cab n figured it was a very small chance both sides blew at once... Besides aren't they the same bulbs as the flashers?

 

Flashers and turn signals usually use the same bulb - single filament bulb. Taillights should be independent from them - dual filament bulb (brake light and taillight). With dual filament bulbs you can have one filament burn out while the other still works.

 

Well no shit, I'm pretty convinced that's not the problem but would be fucking awesome if it was, so I'll check em anyway

 

It's the process of illumination now!

 

Good Call. Anything is possible.

OK - If the relay is GOOD, then you need to be 120% sure. Push in some small jumpers if necessary. No power there means that the ECM isn't telling the relat to turn ON.

1 more check - Do your FRONT SIDE MARKERS and PARKING LIGHTS turn ON?

No Power to - (Front Side Markers / PARKING LIGHTS and Fuse Holder) = We may be done.

 

@PhenixFord I'm like 99% sure, had my gf whos super tiny get in there and she was positive she was on the terminals and had no power... Currently at happy hour, but will check the bulbs when I get back to the house...
As far as the front side markers and parking lights, I'll have to verify when I get back but I think they do work, as far as I've noticed it's only the tails

 

Let's say everything verifies correctly aside from that tail fuse not receiving power... Where does that put me?

 

OK man here is what I'm seeing.

IF - the front PARKING LIGHTS are working then - All the fuses are GOOD and the relay is GOOD. Soo - I'm back to looking for a broken wire (or possibly all bad bulbs?)
IF - NONE of the lights are working then - There is still a couple more things to check.

IF NONE of the lights work - Check these two fuses I have circled in Blue.


I've highlighted the circuit so that you can follow. Both of those fuses must be GOOD before the lights will turn ON. The TAIL RELAY is in the shadowbox. The ECU is directly under the shadowbox. And the Light Switch is directly under the ECU.

In the next drawing, following the yellow highlight, you see the power from the relay passes through the 7.5A fuse. The circuit continues from there to ALL of the PARKING LIGHTS (front and back). This fuse has to be GOOD for any of the lights to work.
IF - FRONTS work & BACKS don't - You have a broken wire.


I'm going to be OffLine for a couple days. Be very through with your checks. Absolutely no room for doubt. If you cant find the problem, there is only 3 thing that we cant check. Probably no alternative except DEALER.

We can't check the relay on the Junction Block
We cant check the output of the switch
We cant check the output of the ECM

Hope this helps Brother. I'll check back when I can.

 

Hell yea brother, I'll get into it deep, and I'll keep you posted... Basically I just moved to the northern virginia/ DC area for a new job that starts Monday, but two weeks of training first so come Sunday I'll be away from my truck for two weeks... But if I can't diagnose this myself then I'll take it to somebody when I'm back to see if I can't at least help them help me... Thanks for all the help brother, I really appreciate it!

 

All the Parking/Tail lights are in parallel

A cut wire in that (any) circuit touching the metal would blow the fuse. You fixed the wire that was pinched at the door. Check the connections at the door mirror leds...

 

I think it's quite obvious that your an engineered and not a field technician.

I am making assumptions:

Could the T-Tap have been placed on [EB1]. Right now we have no idea.
MANY TIMES - I've seen a T-Tap cut the conductor. There is now direct short in this scenario. And the only way to solve the issue is to expose the conductor (at the tap).

PS: Why do you keep leaving circuit elements out of your drawings?

 

Why isn't there an ORANGE wire indicated in any of the posted wiring diagrams?

 

Faded wires or Protanopia...
Looks Beige, and if so, then it's the DRL/TURN with incandescent bulb or just the TURN if LED

 

Not sure on that one guys, all I know is the manufacturer instructions say to splice onto the "off color" wire, white black and "usually orange"
So when I saw orange I was like ok great, and they worked fine up until the door hinge thing