wire harness question

wire harness question

Hello. I bought some 1157 Red LED light bulbs for my rear tail lights. However, when I plug in the LED bulbs into aftermarket wire harness, it doesn't light up. When I put in a regular 1157 bulb into the aftermarket wire harness, it's fine. Anyone know why? And this only occurs for one of the aftermarket wire harness. The other one is fine.

It can't be the wiring because the regular 1157 bulbs work fine. Any ideas?

Also, when I turn on the headlights, the 1157 brake lights on the rear should light up but not all the way (maybe 30%) When I step on the brake, the bulb will light up all the way (100%) However, when I turn on the light, the low lighting(30%) wont light up. I think this is dangerous; espeically at night time. Any ideas on how to fix it?

Currently, one side is using the stock wire harness(with duct tape holding the bulbs in) while the other side is using the aftermarket wire harness.

Any suggestions would be great. Thanks alot

BTW, I drive a '93 Corolla. Thanks

Neo

It may have something to do with the lighting relays not responding to the difference in resistance to the flow of electricity between the LED and the incandescent bulb. Initially, the resistance to the flow of electricity in a filament bulb is extremely low, until the filament heats up. If the resistance is too high initially, it may look like the circuit is still open to the relay and it can't switch it over.

I noticed at NAPA that they sold two different models of 1157 replacement that had identical form factors (that is, they were identical in size and shape) but one was for Dodge, the other for GM and Ford. Electrical characteristics must be the explanation.

Also, check that you have not reversed the polarity on the harness that doesn't work. LEDs only light when the polarity is correct.

I think the LP may have it. It must be a problem with the 3rd party harness possibly a wiring mix-up. Can you get a hold of an ohm meter to check things out?? BTW is the aftermarket harness used for your special tails?? CW