FBI 13" LED

First of all, I thought I'd introduce myself. My name's Taylor and I bought Jeramey's (a member here) Sierra back in June. So I'm pretty new to the bagged scene.

Now onto my question. The truck is running the 13" LEDs for taillights and recently one of them went out (no taillight or turn signal), but it still works as a brakelight. I don't know if it uses a set of LEDs to run the brakelight and another set to run the turn signal/running light or if all the LEDs ran everything. Basically what I'm trying to figure out is if some LEDs burnt out and I need a new LED bar or if it is purely a wiring problem?

I checked out the wiring and it's such a mess that I can't follow everything. There's a TAC unit for each light, but one is using all the wires and the other is only using 2 wires (the one that went out). And then all that is tapped into the trailer plug.

If any of you can follow what I just said and can help me out let me know. I sent an email to FBI, but they never responded back.

Thanks

Who did you send an email to, so I can kick them in the shins?!

It sounds like the wiring is goofed up, but it's possible that the TAC unit is bad...

The best way to find out would be to take the TACs out and bench test them directly to the battery. Here's a quick breakdown of the wiring:

Black Wire- Ground
Red Wire- Brake Light (+)
White Wire- Running Light (+)
Green Wire- Turn Signal (+)

There are two other wires, either a black and a red or two thin black ones, depending on the age of the units. These are your LED connections (red or black with a white stripe for positive, black for ground).

If the TACs are working outside of the truck, then you need to figure out what the previous owner mixed up- it won't be fun, but at least the mess will be gone!

Good luck, and feel free to email me with any questions.

-Phil at FBI

I actually sent the email to you It's cool though, maybe it didn't go through or the spam blocker took it.

I'll try the direct-to-battery test. The weird thing is that they worked fine when I got the truck and just recently stopped. I'm thinking that the guys that installed my alarm system might have messed it up now.

Here's what I'm talking about with the 2 units.

The one is using all the wires

The other isn't using all the wires

And then here's the general clutter

Thanks for the help

I mentioned to the guys here that I needed someone to kick me in the shins, and now there's a line outside my office!!

Those TAC units are OLD... like, 5 years or more!! The last picture gives me a headache trying to trace all of those wires, but I think I see one of your problems- the TAC in the second picture isn't hooked up to an LED! Those two wires on the left are supposed to connect to the LED itself, so if they're unhooked you're not going to get any action out of it.
The other one may work for running lights and brake lights, since you can hook two LEDs up to it, but you definitely won't have turn signals with it wired that way...

Honestly, I think you'd be ahead of the game to just get a voltmeter or test light, figure out which wires do what back there, and start fresh with the installation- that mess is only going to give you problems!

Good luck, and check your IM!

-Phil at FBI

I'm gunna set aside a day to get under there and figure all this out. Working under a bagged truck is nowhere near as nice as working under my old lifted truck

The alarm guy said the LEDs were giving him "feedback" when he was installing it so I'm wondering if he snipped some wires without telling me. I was real confused when I looked and saw that one TAC box wasn't even fully hooked up. I'll let you know what I figure out.