2003 F250 Super Duty Lariet Diesel

[dgruber]

Both tail brake lights out at the same time, brakes only.

Pulled over for this and unaware of the problem.

Cab light works for braking.

Both bulbs look good, but will replace.

All signals work, back up light works, running lights, flashers.

Brake lights will not illuminate when pedal pressed, but cab brake light does work when pedal pressed.

Checked all fuses, but may have missed one pertaining to tail lights as nothing is specified as tail lights or brake lights.

This truck went into shop before 1st 100 miles, due to a electrical problem not allowing the truck to start. This may not be related, but does appear electrical.

[lilvinny]

The problem sounds like your multifunction swtch.Cab light is not wired through it in case of failure.AKA directional/wiper switch.

[dgruber]

Would the Mutifunction Switch also control the flashers?

I do not have a wiring diagram for this model.

But observation when the flashers are on, only the right arrow dash indicator flashes, as if I am making a right turn.

Both tail light's flash properly and directionals flash proper indepenantly.

We have a extended warranty on this vehicle, that hopefully covers this.

These wiring problems are concerning.

Mileage now is 41,870

Who knows how long I have been driving around like this with my family!

It is good they wired around ,or split off ahead of the MFS to the cab stop lamp! At least some warning of stopping for the people behind and tailgaters.

[lilvinny]

Yes the hazzard flasher is part of that swtch also.good luck

[dgruber]

That was the problem.

I took it to the dealer and told them that i suspected the MFS was defective.

The dealer tried to tilt the steering wheel sharpely up and down with the flashers on, while monitoring the instrument panel display flasher indicators. No change in the symptoms.

Two hours later and $50 deductible on the extended warranty, I was on the road with a new MFS switch replaced.

Thank You for the great advise!!!

[lilvinny]

Glad to help