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