Trailer tow charge/back up lights

[mudkaiser]

ok here it goes, early 99 f350 cc longbed 4wd 7.3 6sp. the factory 7way is there and works as it should ive had the truck since 06. I pull a gooseneck trailer with electric brakes with no problems. I recently got a 42' gooseneck with backup lights and a winch with a dedicated battery, so heres where it begins. no power on the backup lights or the battery charge. all fuses are good. there was no relays in the little box between the fusebox and the master cylinder so i put relays in i can hear/feel the backup light relay click when put in reverse but still no power at the plug. am i missing something?

[10secondC]

Get yourself a test light and volt meter and start at the trailer plug.
Trailer Wiring Diagrams | etrailer.com

You may need to wire the plug on the truck side for the reverse lights.

[7.3HeavyHauler]

you may want to take the 7 pin on your truck apart to see if that wire is even connected. theres an electrical schematic on this forum somewhere that should tell you what color the wire is for further troubleshooting.

[mudkaiser]

i have a test light and a voltmeter that ive been using, i never thought that the factory wires wouldnt be connected in the plug? really, ill go check. how can i be sure i have the right relays?

[10secondC]

Originally Posted by 7.3HeavyHauler

you may want to take the 7 pin on your truck apart to see if that wire is even connected. theres an electrical schematic on this forum somewhere that should tell you what color the wire is for further troubleshooting.

Should be black with pink.

[mudkaiser]

took apart the plug, all wires are hooked up traced it back everything is hooked up. im wondering about the correct relay?

[10secondC]

is there a fuse for the revesre lights just for the trailer plug?

[mudkaiser]

yes a fuse and a relay, not sure if i have the correct relay though.

[7.3HeavyHauler]

can't say that i would be correct but seems to me that all the relays are the same, you have 5 posts, 2 for the coil, 1 common, 1 normally open and 1 normally closed. which terminal are you checking for the backup lights, i would imagine its the aux terminal in the middle. as for your batt. charger terminal, as your looking at the receptacle its the top right about 1 o'clock, that should be a 40amp relay and fuse for that. one thing you can do is swap relays with something you know works that would eliminate that possibility. something that just popped into my head is did you get a brand new trailer or did you buy it used from somebody? just wondering if the trailer has issues?

[mudkaiser]

im going to get 2 new relays this morning. im doing the testing without the trailer plugged in.