Originally Posted by flaagan
I replaced the original (and well corroded) running lights and brake / reverse lights on my '72 Ambassador (from Out-of-Doors Mart) and got them all wired in over the weekend. They look great, and I'd definitely recommend them, by the way.
I put a power distribution block by where the TV cable comes in to clean that area up, and I tested the lights by connecting the 12v
power to each point. The running lights work fine by themselves, but when I hook up the power to the left or right turn signals, the running lights come on as well. Any ideas what could be causing this?
- The ground wire that was originally set up for the (aftermarket) stereo was connected to the body panel by the front running lights. They would not come on without that connected there.
- The brake lights do no come on when I put power to what the service manual labels as the Brakes. I'm guessing this is because that's only going to the electronic brake controller?
Thanks for any input you can give on this!
You have some sort of short/open in your wiring. Maybe even a reverse diode connection. You need to check the wires at the umbilical connector.
This bypasses the brake controller and takes it out of the picture.
There is a specific function for each pin in the connector... the large round one in the middle is supposed to be ground.
The 7 pins are: GND, Right turn, Left turn, Stop, Marker, Reverse, 12V
power from/to vehicle (diode may preclude back flow).
Often the 12V pin is larger/more substancial than the others.
LEDS are diodes and as such they usually require the proper polarity to work. Some LEDS are "unipolar" and will work either way... they have more internal circuitry to accomplish this since the LEDS themselves cannot escape their polar nature.
You should be able to test the individual circuits with a 12V auto/marine battery and a couple of wires. First establish a good ground connection between the battery ground (minus) and the ground pin on the connector.
Then you can put power from the plus side of the battery to each of the other 6 pins one at a time and note what each does. Alternatively If you have a functioning trailer battery then you can figure out which pin has 12V on it and then use a wire jumper between that pin and any other pin except the GND pin. If there is a blocking diode in this circuit then no power will be available at the umbilical connector and only a separate battery will work.
I strongly believe that the lights you do not have working will not work from this connector and as such are wired wrong. I would be highly suspect of that funky thing going on with the stereo. You should be able to establish a reasonable ground to any point on the chassis or shell... if not then there is a missing connection between the various ground circuits and the chassis of the trailer. My trailer(s) use the shell as the ground connection on the marker lights... there is only a single wire coming off of them and the second connection is through the screw or rivet you use to attach them to the shell with. I added a solid ground strap to make sure there is an excellent connection between battery minus and the shell/chassis. I also added a similar strap between the umbilical gnd and the chassis/shell. This is done inside the umbilical access panel usually located via a hatch up front in the belly pan. This is so you can replace the hitch connector as needed due to wear and tear.
Hope this helps you to solve the problem...