Ok, here is the deal...at some point the brake/TS lights were replaced with a bad retrofit. The new lights do have 2 wires and the bulbs are multi-filament.
If I do not have the running lights or headlights on, my right TS and brake light work, but the left does nothing. I swapped bulbs and both bulbs work.
If the headlights are on, neither brake nor either TS does anything. My truck matches the industry standard and I plugged the umbilical into the vehicle and verified the voltages at the other end. Someone already installed the self cleaning umbilical port on the camper and the contacts are all clean and greased.
Is anyone aware of an Airstream guide as to what is expected on the umbilical? Mine is wired as this (when connected to my standard truck 7-pin anyway). If the center is pin 1 and then pin 2 is where the alignment guide is and the rest of the pins go sequentially in a CW fashion (looking into the cable connector):
1 = 12V
2 = GND
3 = AUX
4 = Tail Lights
5 = Left TS
6 = Elec Brakes
7 = Right TS
One thing I am not certain about
When the headlights are on the TV and I measure the voltages, both TS and the AUX are steady 13V (using my Fluke DMM). But without the headlights I see both AUX and whichever TS is active pulsing like it should. So it almost seems something is amiss in the TV as well.
Next step is to apply test voltages to the wiring inside at the port connector to determine what is what as best I can.0