Hello, I have a 2004 E350 cutaway that is blowing a fuse in the engine compartment fuse box that operated the tail/running lights in the rear of the van. I do not have the owners manual to tell me what the fuse is so I am not sure if it is just for the rear taillights, or towing lights. I have checked all the wiring in the back and could not find any problems.(with frayed, broken or burnt wires) Could the headlight switch be the cause of this fuse blowing? Every fuse I have put in blows as soon as I turn on the lights. Any ideas on what else I can check? I also have the check engine light on saying it is running rich bank 1 and bank 2, would this be a o2 sensor or something else? Thanks for any help

 

We need some addl info to help isolate just where the problem might be.
Does the fuse blow if only the parking lights are turned on?
If so , keep in mind there are also lights up front that are on that same circuit.
If you have someone to assist, watch the front pkg lites when you first turn on the pkg lites. You may get a clue if you notice one of the parking lites is dimmer for that instant when power is applied. Start looking at that light for a shorted wire, socket etc.
You might also check the rear for a clue , it does save some time and helps get to the problem sooner. If you don't see anything unusual, you might start separating sides, frt ,rear and you can pin down the problem that way. Once you determine which area contains the problem, now you can concentrate on checking everything in just that area. Eventually you will find the problem.
Regarding the check engine lite, With both banks involved, start with checking out the MAF sensor in the intake tubing to the engine.

 

Thanks for the reply, the front parking lights work and look like they are normal. So that leads me to believe that it is in the rear parking light wires or trailer light wires. I am not sure because of no owners manual if this has a trailer parking light fuse and if that is the one blowing. I am going to pull the headlight switch out today as I have read that the wires going to the switch are a problem. I will report back what I find. I wondered about the MAF sensor because when the engine is idle I get a low hum/buzz from the air filter tube. I don't know if it is still present when I set on the gas as I can't hear it over the engine.

 

I have been trying to find the correct power distro box diagram online without any luck however the closest (numbers match my fuse locations) diagram I found is for a 2006 E150 and the fuse number is 24 that blows. On that diagram is says this is for Trailer tow running lamps and back-up lamp relays. A little more investigation revealed my back up lights do not work either.

 

Ok, I have disconnected the two rear plugs under the van going to the taillights replaced the fuse and turned on the parking lights fuse did not blow. I have checked for power at the two plugs, the only plug with power is the brown plug on a brown wire with a white stripe. I reconnected the black plug and the fuse did not blow. So does anyone know what the brown/white wire goes to? I am assuming it is running lights, I have no power on the other three connections in that plug. Should I have power on any other wires with just the parking lights on?

 

Took out the six tail lights (witch include the two back up lights) I should mention the turn signals and brake lights do work. I have two running marker lights still attached, plugged the harness back together and the fuse blew again. All the light plugs and wires look good so now I am going to pull all the wire out of the wire loom and check for problems.

 

Found a shorted wire in the license plate light, problem solved!

 

Thanks for the update ! You zeroed in on that short and it didn't have a chance, lol !