Posted By: abc440
Brake Wiring Question? - 07/26/13 09:20 PM
I have a 71 Charger. Bought a cool looking license frame with led lights. How it is soppose to work is white lights that are hooked up to running lights on car, and turns to red lights when brakes applied, and 1 wire to ground. It works fine when just hooked to a 12 v. battery. I also hooked it up to my 2003 truck and worked fine. It is a Pilot LW704-RW part number. Is there something different on how my car's brakes are wired maybe grounds as opposed to my truck?
THANKS Dave
Posted By: RapidRobert
Re: Brake Wiring Question? - 07/27/13 12:28 AM
I'd think the running lights would go to the license plates white light(s) positive terminal & the brake light switch white wire would go the red lights to fire them when the brake pedal is depressed. The case of the red and white lights or their neg terminal to ground. The white lights would be on anytime the running lights are on & the red lights would be on when the brake pedal is pushed Sound simple but I feel I'm missing something. Me I think it'd be cool to have em flash with the blinkers & not sure how I'd make that work
Posted By: abc440
Re: Brake Wiring Question? - 07/27/13 12:53 AM
Thanks Robert. It sounds simple, but I bought a second one to make it wasnt the light bad. It comes 3 wires-1 groung, 1 wire to running lights, and 1 wire to brake light. The running light(white leds) works with light switch, but red leds or white leds will not work with brake pedal pushed. Tested on truck just fine, and with extra battery I had. (I can touch ground to neg posts, wire for running light white leds good, and touch red also at same time and go to red leds for brakes as they are suppose to). I just tried again, going crazy. They would be nice if they worked. Right now running wire for red leds to running lights. looks ok. Thanks dave.
Posted By: abc440
Re: Brake Wiring Question? - 07/27/13 01:23 PM
The red leds will fire when hooked to parking light, but will not fire when hooked to one of the brake wires in the trunk. also red or white will not fire when hooked to brake wire, but 12 volt test light will fire when touching brake wire.
Posted By: abc440
Re: Brake Wiring Question? - 07/27/13 09:39 PM
Hey, I think I just discovered my problem. Dumb me, I just hooked a volt meter to brake wire in trunk and only had 6.9 volts. I can start car and at idle have 9 volts and led lights on license frame work like they suppose to. That explains why they would work when hooked straight to battery. I was just using a 12 volt trouble light to test with. Is that amount of voltage to trunk brake wires normal, or how can I get more. My oringal brake lights work ok, even with car not running. Any suggestions? Thanks Dave
Posted By: RapidRobert
Re: Brake Wiring Question? - 07/27/13 11:22 PM
That would have got by me as I did not know that LED lights needed more voltage than regular lights in fact since they're more efficient I'd have thought the opposite that they work on less. That is REAL LOW voltage tho. I'd double check the meter readings by running the ground lead all the way up to the batt neg post. I'd clean EVERY connection & I'd see what I have for charging voltage at a fast idle at the batt & at the alt & see what you have at the bulkhead/fuse box etc & go from there rearward. Any terminal/connection is a potential voltage drop from high resistance
Posted By: stumpy
Re: Brake Wiring Question? - 07/27/13 11:31 PM
You should have battery voltage,12v+,at the rear lights.
Posted By: abc440
Re: Brake Wiring Question? - 07/28/13 10:56 PM
I ran a groung wire straight from battery (not running) and got 7 volts at brake wire in trunk. Checked voltage on battery not running and got 12.25 v, got 13.5 volts with motor running at 1500 rpms. Tried to check voltage at alt (3 wires) not sure which wires to touch and a little intimidated. To be honest, I hate to bother bulk head connection if no other problems. Thanks Dave