2005 Mustang 4.0 Raxiom sequential taillights act up when headlights are turned on


Dec 11, 2019
Lansing, MI
Title. With the headlights off and the hazards on, both driver's side and passenger side taillights sequence normally.

However, when I turn on the headlights and hazards:
- The left-most driver's side taillight stays constantly on and increases and decreases in brightness only, while the middle and right driver's side tail light flash on and off sequentially.
- The passenger side taillights sequence normally, but only the brightness increases and decreases sequentially, instead of flashing on and off sequentially.

It can't be the bulbs since they work normally with the headlights off, is it 100% a short, and would buying a replacement wiring harness solve the issue? I should mention I've had them for almost 5 months. The raxiom taillights I'm talking about is the $110 plug-and-play kit from AmericanMuscle
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Active Member
Jan 25, 2020
Not sure about Raxiom. I just put Spec D sequential led tails on mine. Work perfectly. However, they are almost three times the price of what you paid. But I'm a firm believer in "you get what you pay for." There was no wiring harness involved, everything was pre-wired and all I had to do was stick two items to the body before installing them, they already had two-sided tape on them. Then they plugged right in to the existing stock harness.

Bought them from CARiD.