Trailer left turn don't work
Asked by Dupree51 Oct 03, 2019 at 12:05 PM about the 2017 Ford F-250 Super Duty XLT Crew Cab LB 4WD
Question type: Maintenance & Repair
The left turn signal on my trailer doesn't work. No
power from truck . the el. Diagram called for relay
20 for left turn/stop. No relay 18,19,20,21 in pdb
under hood. Where else could they be?
4 Answers
Dirty or corroded connections at the bumper can be at fault.
Fyi this 2017f250 has a trailer light processor under the dash to the left of the brake pedal. The print for trailer lights call for relays 18,19,20,21 to operate trailer lights. This is a solid state processor don't bother removing it to check relays. The problem was in the plug that connects the truck wiring to the bumper mounted plug.
I always plug and unplug the connector several times to clean off dirt when connecting the trailer.
And some times it the light has corroded I even had a new trailer with a cheap wire connect inside the light housing broke lose check your trailer first
