My 99 f350 rear lights (running lights & license plate lights) aren't coming on. Headlights are working though. Any suggestions?

 

The front and rear lights share the same switch and fuse, so your problem is most likely in the wiring.

The running lights are powered by a brown wire in the harness. All of the lights that are not working on your truck also share a common ground point.

Chris

 

id say its a bad ground or feed..... just need to start checking.

 

I found a schematic for a 2003, do you think that's pretty much identical? Would the headlights have a different ground point than the running lights? Also, does that brown wire come right off of the selector switch inside the cab?

 

Don't know for sure about the differences between 99 and 03.

Here are a few wiring diagrams for 1999:









The headlights would not be grounded at the same point as the rear running lights.

Yes, the brown wire starts at the main light switch in the cab.

Chris

 

Anyone know what the green wire is coming from the harness on the left side of the frame rail that connects into the tail light & license plate lights connector? I check some grounds nearby & they appear ok. But there is a green wire that comes out of the connector/harness which isn't connected. This harness houses 6 wires, from what I know it should just be the brown for power & black for ground but this green wire is throwing me off & may have something to do with my problem. Thanks

 

Are your brake, turn signal and reverse lights working? If not you may want to check the pigtail that connects the harness attached to the bed with the rest of the wiring on the frame of the truck

 

Yes the brake, reverse, & turn signals were working. Just the rear nighttime running lights & license plate were out. Only thing I can think of is there is the trailer hookup & also a hookup in the bed that are all spliced together so maybe that brown wire came loose there somewhere....?

 

check the Fuse. I had this happen to me before.

 

? could a faulty light switch cause this, not expert on this but something to look into.

 

This happened to me once, and it eneded up being the plug to the switch in the column.

I did eventually have to replace the switch, but I was able to tie wrap the plug to the switch for a year or so before i needed to replace the switch.

 

Tail lights used to be tied with dash lights, if dash lights were not working you knew that the tail lights were probably out too. Dash and tail/running lights may be on a fuse of their own. If you have an owners manual, it should have a fuse guide.

 

No interior/dash lights all work & no owners manual either. I checked some of the fuses which I think the Haynes manual called out & they were all good. I'll keep looking this weekend. Thanks everyone, really appreciate the help!

 

Dont forget the fuse box under the hood at the drivers side firewall. I used to have a small short that would blow my parking lights every so often. Until I found it and got it fix, I replaced the fuses for the tail lights 3 times in each location. Under dash and under hood.

 

I wasn't aware there were fuses for lights under dash, I thought those were just located under the good on the drivers side. Do you remember which position those were under the dash by any chance?