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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6641
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
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I have a E350 Ford Motorhome. The tail lights are not

Customer Question

I have a E350 Ford Motorhome. The tail lights are not working. Brake lights and blinker work. Are the running lights connected together? How do I tell what the problem is. Have checked wires on back lights and bulbs and fuses? what next? there is one running light on top of the motor home that has cover missing. How do I tell which running light is causing the problem and if one doesn't work does that make none of them work?
Submitted: 1 year ago.
Category: Ford
Expert:  A. Penland replied 1 year ago.

Turn just the parking lights on and look at the front of the motorhome. The lights to the outside of the headlights should be on. Let me know if any of the marker lights or parking lights are on. Walk all around the motorhome.

Just the parking lights.

Customer: replied 1 year ago.
How does that help? Not parkiG lights running lights.
Expert:  A. Penland replied 1 year ago.

The parking lights and the running lights are all on the same circuit.

Customer: replied 1 year ago.
Have front parking lights no back parking lights but blinker and break light work in back. Only running lights and back parking lights do t work
Customer: replied 1 year ago.
No runner lights around whole trailer or back lights
Customer: replied 1 year ago.
Told u this info from start. Said no running lights or tail lights all other lights work
Expert:  A. Penland replied 1 year ago.

For the trailer lights, check fuse "P" in the engine bay fuse box.

But since the front parking/running lights work, you have a broken wire for the parking light circuit between the headlight switch and the rear tail lights. The ground to the tails lights is good because the brake and turn signal lights work. There should be a connector under the rear of the vehicle on the frame. That is where the aftermarket motor home companies tap into the factory harness.

Customer: replied 1 year ago.
There r several wires to the connector. Is there a way to test to see which one is bad?
Customer: replied 1 year ago.
None of wires to connector Look broken. Is there a way to tell which one is bad
Customer: replied 1 year ago.
They were all taped and look good condition
Expert:  A. Penland replied 1 year ago.

The parking/running light circuit is the brown wire.

The connector should have 12 wires in it.

Customer: replied 1 year ago.
All wires look connected. Several wires
Customer: replied 1 year ago.
Primal casing around wires still in tact
Expert:  A. Penland replied 1 year ago.

Do you have a meter to do a few electrical tests?

Customer: replied 1 year ago.
No will just have to take to Rv repair . Checked all these before I called you, do t see how wore is bad if they are all still I'm casing and look good. Disappointed
Expert:  A. Penland replied 1 year ago.

The wire could be broken between the connectors in the harness running along the frame or up in the body of the motor home. There is no common place for the wires to brake. Since it is an RV, the wires are running different than factory Ford harnesses are once they enter the body.

Customer: replied 1 year ago.
I'm s girl and know nothing about cars. Had a friend checking ur suggestions, said followed wire all the way under Rv and saw no problem. Sounds like something mechanic only would have tools to check. Disappointed
Expert:  A. Penland replied 1 year ago.

Sorry I could not help you locate the problem. But to properly find it, you will need a meter to check for voltage through the wires from the tail lights back to the headlight switch. There is only one fuse for the parking/running lights and since the front parking/running lights work, the fuse is good and so is the switch. That only leaves the wiring.