Hey guys I'm new here and I have a 2006 Ford Mustang GT. Last year I installed the sequential kit for the rear lights from American Muscle and I noticed when installing them that my reverse bulb was out on the driver side. It has to be the part of the wire other than the harness, because with either the stock harness or the aftermarket sequential harness, the reverse bulb still wouldn't light up. I tried replacing the bulb and that didn't work either. Then today I noticed that the license plate bulb is out and it's not the bulb either. The weird thing is that I swear the license plate bulb was working for a while, but none the less, I'm sure it's related to the driver side reverse bulb not working, as the license plate socket seems to be wired to the left harness according to Reply #8 at https://themustangsource.com/forums/...-light-461123/. I should note that the other reverse light, parking lights, headlights, dome lights, 3rd brake light, and brake lights work, so it's only these two bulbs that are not. Do you guys think it could be an issue down the line of the wire somewhere or maybe an issue with the Smart Junction Box? I find it strange how the driver side brake light works fine, but maybe the reverse and license plate bulb are wired together, and separate from the brake light.

 

My mechanic and I believe it stems from the junction box under the passenger side dash. It's probably from water getting there. I cleaned out the water catches a little while back, but does anyone know a solution for stopping water from getting in the passenger side? I'll probably need a new junction box there. Thank you!

 

The license plate lamp is it's own run from the SJB:

http://iihs.net/fsm/?d=40&f=Parking,...0Lamps.pdf&p=3

So it is not connected to the left reverse light except perhaps somewhere in the SJB.

The reverse lights are thus:

http://iihs.net/fsm/?d=40&f=Reversing%20Lamps.pdf

There are two separate wires for those, and they're activated directly from the SJB.

Whatever is causing the issue is likely to be a wiring problem upstream of the lamps and perhaps even the trunk. It could be crusties at the SJB, and the older ones before the TSB could be subject to water contamination and corrosion due to leaks. You may want to check the SJB. Otherwise, you need to check end-to-end each wire to see if they're good. I bet you find a cut/corrosion issue somewhere.

Good luck, hope that helps, and welcome to the forums!

 

The biggest culprit for getting the SJB wet in the 2005-2009 Mustangs is located in the cabin air filter cubby, in the passenger side cowl under the hood.

That filter cubby has small drain holes in the bottom. If they become clogged with debris, water can build up and eventually wets down the SJB and passenger side carpet. You will also get to enjoy the somewhat musty smell of wet carpet and a wet cabin air filter to go with assorted electrical gremlins.

 

Thank you so much! This is exactly the info I was looking for. I bet it is from the SJB at this point, due to the crusties. I read on another post that a guy wrapped his SJB in a black garbage bag with electrical tape. Thank you for the welcoming! I should have joined years ago.

 

I just realized I can do a multi quote lol. Thank you, that is also exactly what I was looking for. I believe I cleared those out a while ago, but perhaps they got clogged again. I noticed the area gap near the side mirrors was a bit rusted on both sides, so I wonder if water is getting under there at all too. I'll have to trace it down. Do some people have water coming through any where like the side mirrors? I'm thinking that maybe if I can't stop the water, then I can just cover the SJB.