Brake Controller?

[First Light]

On the 5 wire flat plugs for use with surge brakes the 5th wire is blue and it goes to back up lights.
I assumed it was what the op was talking about since he said it was taped to the harness wiring. Sorry was posting while half asleep.

Yes, a blue wire is normally for back-up lights. But when used with a trailer that has surge brakes, the blue/5th wire is energized when you put the transmission in reverse so as to by-pass the surge brake solenoid when backing, so the surge brakes will not engage when in reverse.

 

[mtondreo]

I tried putting a 12v light on my blue wire tonight while in reverse and got nothing. My expy does not have the factory heavy tow package but was looking for an easy way to get a signal to a rear camera. Can someone confirm this-maybe it is just low voltage or maybe I have to install some relays or fuses before that wire even becomes active. Thanks in advance, Mike.

 

[RUFFSTUFF]

The blue wire is not connected to anything on either end.

 

[ELVATO]

I tried putting a 12v light on my blue wire tonight while in reverse and got nothing. My expy does not have the factory heavy tow package but was looking for an easy way to get a signal to a rear camera. Can someone confirm this-maybe it is just low voltage or maybe I have to install some relays or fuses before that wire even becomes active. Thanks in advance, Mike.

Just tap into the reverse lights. Or, try the purple wire on your 7 pin round plug.