Troubleshooting Left Turn and Running Light Trailer Functions on a 1997 Ford F-350 4x4

Published 01/30/2019

Products Featured in This Question

7-Way Pre-Wired Car Connector, 7' Lead

(75)

$91.03

14 Gauge Wire - Yellow Primary - Per Foot

(48)

$0.48

Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 5

(1104)

$8.52

Hook Probe Circuit Tester

(61)

$13.33

Question:

97 Ford F350 4x4 has factory trailer harness. I tested each wire before cutting factory harness plugs 2 to install a generic plug for a truck bed. Tested each wire before splicing new plug on. I did it slowly. all wires produced voltage in their respective positions. Upon plugging into the new bed and testing, I have no left turn or parking lights. But i have right turn, 12v charge. Im thinking Multi- position switch has issues. Possible? all fuses test ok.

asked by: Rich W

Expert Reply:

It sounds like you spliced in a second 7-Way connector like part # 20023 to the current 7-Way wiring on your 1997 Ford F-350 for an in-bed camper and the lights on the camper aren't working. Is the original 7-Way testing correctly? If it is but the in-bed 7-Way isn't testing correctly then you have isolated the issue to the wiring harness that you installed. If neither are working correctly then I would try testing the wiring before the splice with a circuit tester like part # PTW2993 to see if you are getting power to that location or not.

Once you find where the signal ends then you will want to replace any sections that aren't working. If it is just your left turn and running lights, then you can use 14 Gauge Wire # DW02412-1 and Butt Connectors # DW05744-5.

Attached is a helpful article on troubleshooting wiring for you to reference as well.

expert reply by: Jon G