Having just done this task, I found out the following:

1. Make sure the gound is working by using a resistance checker and making
sure there is none/minimal between the trailer and the vehicle. Using the
hitch to ensure a good ground is iffy at best, since most people grease the
ball or the inside of the hitch to prevent wear and tear. Grease does not
conduct electricity well at all.

2. The yellow goes to the right side turn signal while the green goes to the
left side turn signal.

3. The brown goes to parking lamps only.

The 1157 bulb uses two filaments, the brighter of which is for brakes. If
you wire up the lights to have the brighter on with the parking lamps, then
you have the socket/light assembly wired backwards.

This article may also help:
http://www.popularmechanics.com/auto...c/1272556.html

Ed Stammer

"rich" wrote in message
. ..
Hmmmmm Maybe I could just tie a red flashlight to the stern of the boat
to make up for the missing "parking" lights....

It is a Ford 2005 Expedition. It has the "factory" module already
installed and the output is both a seven pin and a four way flat. The
four way flat is what I am using. Testing of the pins on the seven pin
outlet seems to follow the correct outputs.... as printed on the plastic
dust cover. The four way flat has been tested with a little "trailer
tester" with three LEDS. The "parking brake" LED glows brightly; and the
Turn indicators ( both L & R) glow in a flashing manner when the vehicle
is set to use the turn indicators. Everything on the auto side seems to
be ok..after I changed out one of seven ( I think ) TRAILER fuses ( the
left turn indicator fuse ) in this vehicle. After hooking everything up
and having everything work ( except the parking lights) the fuse remains
intact.

I think that the same Vehicle and hook-up works OK on my trailer (that is
1200 miles away in another State) with the same High PVC uprights and the
very same red/black light units attached. My foggy brain tells me that I
ran into something similar when I hooked that rig up...but I honestly
don't remember what I did to solve it.. It probably was my usual "trail
and error" and I probably reversed the two leads.

Any further help appreciated. RichG TX/IL