I have a 2003 E350 14ft box truck. The box sits about 11'6 tall.The running lights and clearance lights don't come on when I pull the headlight switch. The brake lights, headlights and blinkers still works though. What could be the possible causes of this problem?

 

Look for a blown fuse. Many times they have a separate fuse just for the body clearance lights.

 

I checked all fuses. Both in the cab and under the hood, and all seem well. Any other suggestions?

 

Not being there I have to ask this question, have any of the corner lamps met with anything like tree branches where the light was damaged and the feed wire opened or grounded?
If not, then you will need to go under the driver's side front of the body and look for the wire that comes from the light switch and goes to the body lights. Once you find it check if it has power there. Depending on what you find there will determine if you go back to the cab where the wire originates or to the body here the wire may be broken or possible have a corroded connection because many times when the body is installed they don't use shrink connectors and over time the butt connectors corrode and lose contact.

 

Actually one of the corner lamp broken. The back passenger side clearance lamp. Its located at the top off the box.

 

Take a meter and check to see if you have power going to the lamp with the light switch turned on. If the lamp has power, check the grounding of the lamp circuit between the box and the frame of the vehicle. The ground could be bad.

If there is no power to the lamp you will have to find out where the break is in the power circuit. Either a blown fuse, broken wire, or a bad connector.

Frank

 

If you look carefully you will find that the wire/or bulb holder in that damaged lamp probably is up against a part of the aluminum rail producing a direct short. Just separate the wire and parts of the bulb holder and you may even see the problem once you look at it. Once you see the damage and problem you will know what to do . If not just ask.