Trailer Wiring Harness for a 2014 Mack Truck Granite

Question:

on a 2014 mack granite can u feed power from the red hot brake to right and left turn to get stop lights on an electric trailer

asked by: Eric

Expert Reply:

A trailer traditionally uses combined turn and brake lights like you have described. However, you will need the proper wiring harness for your 2014 Mack truck. We do not have a listing for heavy duty vehicles but if it needs a harness and it has combined brake and turn lights you could use # 18252.

If the truck already has a harness but the trailer has separate brake and turn lights you can use converter # 118158 to separate out the combined signals. I have included a picture showing how it would wire up.

If you had one brake circuit going to both turn signals that could result in both lights blinking on the trailer when the turn signal is on due to back feeding.

expert reply by: Michael H