Hi there,

I have no trailer package from factory. The trailer is not hooked up. I have 4 prong connector

I am showing all the correct voltage for brake and signaling but I get 0V for running lights for trailer (brown wire) at the plug using DVM.

Gnd plug - to blk on voltage meter
Brown plug - to red on voltage meter

Cover up "eye" phizo sensor ON DASH - i think it's called that - thus trigger Daytime running lights. Perhaps not applicable but it's on. Also turned on full lights switch to top direction.

No 12 V found on BROWN wire.

Things I have done:

Turned blinkers on key in on position

Tested the following fuses with probe light!
TRL LTRN - 10AMP - PASS
TRL RTRN - 10 AMP - PASS

TRL B/U - Fuse okay visually but no PROBE LIGHT ON ( trailer backup lights???) which of course i don't use or have anyway. so OK TO IGNORE I ASSUME

TRLPRK - 10 AMP - PASS

Gosh if the green and yellow check out using the GND and they work, that means GND should work.

Thanks guys.

 

Well if all fuses are good and we know ground works since brake lights , I figured why not start undoing all the electrical tape and follow it back, I found a huge "CLUMP" where someone had used butt connectors .. sure enough

YEEE OLD BROWN WIRE WAS corroded off.

Repairing and will re-test.