TEM48 are you referring to the wire harness for the 7-pin plug or a different wire harness that might be specific to your model?
Is this the
Brake Rite EHB you are going to be using.
On
MY unit the colors are:
Ground_____white mostly with a few green
Brake____blue in 7 pin harness, blue wire attached at harness and routed to breakaway
On board battery(+12)____black
Tow Vehicle +12____black
Breakaway +/-____blue from harness, Yellow with black strip the second wire connected to the switch, where this wire is routed...don't know.
The TV 12v power from the 7-pin plug on my unit is connected to a 40amp auto-reset breaker, the other terminal goes to the battery. Do you have one of these visible?
Hope this helped.