Minor Trunk Electrical Problem - Not a Fuse

Car: 1998 Mustang GT Convertible M5
Location: Trunk
Symptoms: Trunk light out, sequentials out. These get their power from the same source.
Side notes: I can jump the sequential unit directly to the battery (+) and they work. Same with the trunk light. I checked fuse 8 in the I/P fuse panel, it's good. I checked the 50A fuse under the hood, it's fine as well. Both have power and fuses are good as tested.

Possible Causes: Bad Remote Keyless Entry Module (I do not know how to diagnose this), Bad Upstream Wiring (I do not know how to trace this)

In my trunk on the harness that goes up to the third brake light and trunk latch assembly, one of the wires provides a constant 12V. When I test the wire with a multimeter when it's unplugged, it shows 12V just fine. When I test it for resistance, it shows a 0, no resistance. Now, when I plug it in (put a load on it) and test for voltage, it varies from 4V to 7V.

I'm not an electrician by any means, but I think some of you guys may be able to help me.

If you need any more information, please ask.

Thanks pally wally's! :SNSign:

Anyone?

Superhereaux said:

the sequentials don't work but do the regular turn signals work?

Click to expand...

Since the kit required swapping 2 of the lights (inboard to center, center to inboard), and also intercepting the wires to the outer lights, only the inboard lights light up when I brake and/or signal to turn. The third brake light works fine (12V sent when brake is pressed), as well as the license plate lights (12V sent when parking lights are on).

So yes, the sequential kits does not work because it is not getting power, but the inboard lights do work for normal braking/signaling.

No, I would like one though if anyone has one.

I've traced it to between the I/P fuse panel and the trunk harness.

For a temporary fix, I tapped the sequential kit into the park light 12v wire. Now the sequentials will work as long as the park lights are on. I'd really like to fix the constant 12v line though!