trailer brake and turn signals not working

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tinstar26
Posts: 3
Joined: Fri Nov 28, 2014 3:51 pm

trailer brake and turn signals not working

Unread post by tinstar26 » Fri Nov 28, 2014 4:13 pm

The trailer and brake lights have stopped working. Fuses under dash check good. Under the hood are two boxes. One next to firewall has a large relay and two smaller ones. The other box has two of the large relays. The smaller ones click when the turn signals are on. Changed all relays in this box still nothing at plug. Vehicle is a 2004 f250 with a 5.4 motor. Need help

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carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: trailer brake and turn signals not working

Unread post by carriedi » Fri Nov 28, 2014 11:15 pm

the part that has three relays is for parking lamp, reverse lamps and the trailer battery charging.

the part that has two relays is for the left turn and right turn trailer lights. The fuse for the turn lights to the turn relays is fuse #6 (20A) and the parking or tail lights is the other fuse, #38 (20A). Fuse #6 goes out from the fuse as a dark green and orange wire. the fuse #38 goes directly to the relay. (no external wiring)

If the power from the fuse is good and you can hear the relay clicking, most likely there is a problem with the wiring going back to the trailer plugin. Have you check the trailer plugin to see if the trailer socket has power there or not?

wire from the turn relays is going to be dark green for right turn, and yellow for left turn. They should go all the way from the relay to the trailer socket. \

wire for the parking lights should be a brown and white wire from the relay to the trailer socket.

check for the correct power out and the wiring right by the relays and then check it back by the trailer socket.

Make sure you have a good ground at you trailer socket too. That affects all the trailer wiring.
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tinstar26
Posts: 3
Joined: Fri Nov 28, 2014 3:51 pm

Re: trailer brake and turn signals not working

Unread post by tinstar26 » Sat Nov 29, 2014 8:48 am

There is power to the running lights and electric brake at the pig tail on the rear. The part with three fuses is where I hear clicking when the turn d goals are on I also can feel it vibrate to. So to make sure I understand, the box with two relays are for the signals and brake lights.

tinstar26
Posts: 3
Joined: Fri Nov 28, 2014 3:51 pm

Re: trailer brake and turn signals not working

Unread post by tinstar26 » Sat Nov 29, 2014 1:37 pm

Found the trouble. It is in the connector to the pig tail at the rear. Shorting out. Thanks for the help

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