Should be no power on any of the 4 wires until you turn on the headlight switch, press the brakes and/or hit the turn signals. Thanks Bill. So then with brake pedal down , light switch pulled out ,power should be to all 4 wires to the rear? Yes, assuming the turn signal switch is in the center position.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12
'52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
| 
