Join Date: Jul 2007
Location: wasilla, Alaska
Sequential LED tailliight problems
Any ideas are greatly appreciated.
I have a set of GT500 sequential taillights in my 68. I don't know the brand name but I purchased them from themustangshop in WA.
The sequential circuit board plugs into the flasher plug and is also grounded to the metal dash.
Since I purchased them, they have never worked right. Everything works great when the key is off, accessory and even in run (turn signal only with acc and on position). But, once the car is running, the taillights won't work, brake lights or turn signals. Sometimes there will be a little blip of light but that's it.
The kit's led panels was a plug and play with my factory 1157 receptical. That is grounded twice, once through the wire loom and one externally to the tail panel.
I have traced down and tested the turn signal and brake wiring from the dash all the way back with a test light and volt meter. I have 11.3 v when the car is not running and 14.30 v when it is running all the way to the plug at the taillights.
I disconnected the alt thinking 14+ is too much for the LED's. No luck.
Here's one thing that is strange. I unplugged the LED panels at the factory plug and popped a 1157 in and the damn thing works perfect with the car running. I can't understand why the LEDs won't work with the engine running. Is it possible I need a condensor? Could it be electronic noise that's killing them?