1993 F350 electrical problems

[Daniel McCurdy]

The truck is a 1993 Ford F350 crew cab long Bed 7.3idi 2wd. The back passenger tail light works when the headlights are off but are dim. When the brakes are pushed while the headlights are on it goes out but the driver side tailight works fine as does all the other lights. I'm thinking it's a ground but don't know where the grounds are so if anybody knows what grounds to check and if it's something other than a ground I would greatly appreciate it.

 

[IDIBRONCO]

It's also possible that it's a bad tail light bulb socket.

 

[Daniel McCurdy]

Well I ran a ground wire from the battery to the tail light ground and everything worked perfect and was nice and bright. So if seems like it's a ground. Would a bad bulb light socket work like that?

 

[franklin2]

Well I ran a ground wire from the battery to the tail light ground and everything worked perfect and was nice and bright. So if seems like it's a ground. Would a bad bulb light socket work like that?

Depends on where you stuck the experimental ground. If you stuck the ground wire beside the bulb itself when it was in the socket, then yes it could be the socket. If you put the ground wire onto the factory ground wire after it leaves the socket, it's not going to be the socket.

If the other side light works fine, sounds like it's a splice in the ground wires back there. All the lights are tied to one ground wire running up front. There are factory splices in the wiring and sometimes they corrode.

Not sure where they ran the ground wire in 1993. In the mid to late 80's trucks the ground for the rear ran all the way up front and was bolted to the firewall behind the radio.

 

[Daniel McCurdy]

I stuck the experimental ground to the wire going to the socket

 

[steve phillips]

Ground Points - Ford Truck Enthusiasts Forums (ford-trucks.com) maybe this will be of some help.