Hello,

I recently bought a 1999 F-250 Super Duty. I am having a problem with the factory wiring harness.

I plugged in my trailer to test it out and found that the left turn signal and left brake light did not work. The trailer works just fine on another vehicle. So I decided to take a look at the harness that was plugged into the factory plug. The harness that plugs into the factory plug is spliced to hell and is in need of replacement. I decided to test the factory plug's yellow wire to see if it was indeed working before scraping the old harness. The yellow plug on the factory harness does not give any voltage when the left turn signal is on. I am planning on ordering a new harness to plug in but I want some advice on what else I can check before I just splice it in to the left turn signal wire.

Here is the harness I am going to order as it is all one piece. The "factory harness" that I keep refering to is what the grey end plugs into.

 

There are individual fuses for the trailer connector. Left turn/stop is fuse #1 in the fuse box under the hood.

Fuse information can be found in your owners manual, which you can get online here if you don't have one.

https://www.fleet.ford.com/maintenan...ls/default.asp

 

Before ordering, have you seen the 4:7 plugs? They have both the 4 flat and the 7rv on the same box. It's handy if you run trailers with both kinds of plugs.

Check the fuses, but it's still nice to have clean connections and harnesses.

 

Thanks guys, I will check the fuses in a bit.

Also, I do want a 2 in 1 box as that is what is on there now. However the person just bought a hopkins and spliced it into the OEM connector. I cannot find a 2 in 1 box that terminates into that grey OEM connector. This was the only one that I found. Any suggestions would be appreciated!

Jordan

 

Fuse was blown! Awesome.

Now just looking for new 2 in 1 to OEM connector suggestions and I am on my way!!

 

Try Ed the Parts Guy. He has great prices on all the OEM stuff. I don't know if a newer 4/7 pigtail will fit on an older truck but he would. Go to his web page and send him a message.

http://www.partsguyed.com/

 

E-mail sent to Ed. Thanks!

 

Hoppy used to the early superduty connector. I just checked their website, and it's not listed with the grey connector. However, in the picture you show, the harness has both the round and the square end. If you don't find what you want, you can get both, unplug the 7rv to get the large round plug that plugs into the 40955.