Trailer lights not working please help!!!!
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Senior User
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From: Minnesota
Trailer lights not working please help!!!!
I have a 1999 F150 with the 9 pin connector for my trailer I plugged my trailer in today and the lights came on for a little while then quit working my blinkers and brake lights work fine just no lights?? I checked fuses and didn't find any bad ones I cleaned the connections and checked the trailer with a different truck and the trailer lights work fine! so what am I missing???
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Senior User
Joined: Aug 2004
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From: Minnesota
I have a 1999 F150 with the 9 pin connector for my trailer I plugged my trailer in today and the lights came on for a little while then quit working my blinkers and brake lights work fine just no lights?? I checked fuses and didn't find any bad ones I cleaned the connections and checked the trailer with a different truck and the trailer lights work fine! so what am I missing???
Senior User
Joined: Mar 2004
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From: York, PA
Just to clarify:
When you say you are not getting any power to the pin on the trailer connector you are checking that with a test light or multi meter; correct?
When you say you are not getting any power to the pin on the trailer connector you are checking that with a test light or multi meter; correct?
Fleet Owner
Joined: Mar 2012
Posts: 26,118
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From: Near Cal. Avenue
You probably have a poor ground as they originally worked and went out. Circuit resistance increased with poor ground/connection. Double check all your connections at the rear of the truck for a bad one. Possibly even a leaking lense letting water/moisture in. Remove the assemblies and search.
Freshman User
Joined: Mar 2012
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I had the exact same problem last week. It ended up being one of the fuses under the hood. I don't remember which one though. The description in the owners manual was kinda not real clear though I remember. You could pull the fuses under the hood one at a time to see which one is blown and that will probably be the one that will fix it.
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Elder User
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The under the bumper 7 pin socket is famous for a bad ground connection, Check the large white wire connection on the back of the socket. If you suspect a bad ground, use a jumper cable from the truck frame to the trailer frame, see if that makes a difference.
This ground problem usually shows itself if you have a lot of rain, or go through a car wash, just before hooking up the trailer. The factory socket can trap and hold water for quite a while.
Easiest way to test the truck socket is with a trailer emulator. It's a LED test plug, that simulates the male end of the connection. They are about $25.00 at trailer/RV parts places.
Dave
This ground problem usually shows itself if you have a lot of rain, or go through a car wash, just before hooking up the trailer. The factory socket can trap and hold water for quite a while.
Easiest way to test the truck socket is with a trailer emulator. It's a LED test plug, that simulates the male end of the connection. They are about $25.00 at trailer/RV parts places.
Dave
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Senior User
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From: Minnesota
Both test light and multi meter
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Senior User
Joined: Aug 2004
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From: Minnesota
well I checked every fuse in the cab and under the hood they were all good checked the voltage on fuse #201 for trailer running lights it was at 12V so I checked the ground out back it was good but I cleaned it up on the inside of the frame where it attaches to the frame! I then checked the power at the plug connection before the rear spit for the tail lights and found it still had power then check the wire about 3 inches before the 7 pin connector and had power there but nothing on the pin so I pulled out the pin and found the wire was bad going into the pin so I cut the bad part of the wire then soddered it back together and now they work fine thanks for the help!
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