No Tail/running lights

I'm having a problem with my tail/running lights on my 95 2720SL and was wondering if anyone else has run into this or knows of any "wiring pinch points" I should be aware of.
Symptoms:
All other exterior lights are fine (which to me indicates a good ground) but none of the tail/running lights will light.

According to my manual, the green wire is the tail/running lights and the white wire is ground. I've used a multimeter to check the terminal block and found  no voltage between these terminals with everything connected, but am able to get 12V to ground at the terminal block when only the hitch harness side is connected (disconnected the trailer side from the terminal block). This verifies good connection from tow vehicle.

I then traced the wiring back to the street side wheel where I found the splice with two other green wires.
I separated them and verified 12V to ground on the wire coming from the hitch, but when splicing just one or the other of the remaining green wires to that one, I expected one to work properly and one to show a problem. To my dismay, both voltage levels dropped to zero. (does this indicate a short on both trunks?)

After that point, tracing becomes difficult because the green wires head up through the floor and become lost in the back of the cabinet. I took off the outside refridge vents but didn't find any problems.

I also removed all the running light bulbs so all that remained were the tail lights. No tail/running light voltage reading at any of the sockets(including tail lights).

Well, I thought I'd bring in the calvary,any help is truly appreciated.

[Bill]

I doubt that the problem is a short, or you'd be blowing fuses.  It sounds to me like you have a high-resistance connection somewhere between the terminal block and the tow-vehicle's light switch.  When you remove the load (i.e., disconnect the lights or remove the bulbs), your multimeter can see the 12 volt source even through the high resistance connection.  However, when you hook up the bulbs and start to draw current, virtually all of the 12 volts is dropped across the high-resistance connection.

The most likely place for a high-resistance connection to develop (though not the only one) is in the 7-pin connectors between the tow vehicle and the trailer.  It happens because water gets into the connector and causes corrosion, and it can happen in either half of the connector.  I suggest you open up these connectors until you can see the physical connection point of each wire.  I bet you will find that one of them is corroded almost all the way through.

Let us know the result.

Bill

Thanks for the response Bill,

I checked trailer side 7 connector and it is a molded unit. but just as you suspected, I could see evidence of corrosion in the pins and used a small flathead screw driver to clean it as best I can.

It works!  If I have any further problems I'll replace the connector.

Thanks again, It always helps to get a fresh perspective.

Happy Camping,
Carl