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gregRV · 10-19-2012, 01:31 PM

2000 Ford Class C MM - E450 chassis. Right "Rear" turn signal and brake light won't work. Right "front" turn signal works, all running lights work, Left front/rear turn signal and brake light works.

I have a 4 wire system (yellow=Left Turn/Brake, Green=right turn/brake, Brown=lights, white=ground.

The same problem applies to the towing circuit. Left turn/brake works okay. Right turn/brake does not work. Running lights work.

I have traced the Green wire through two connections toward the front of the Chassis - the Green wire is dead (except when I turn on the running lights and then it registers 1.5 V). The yellow line has a varying signal when the left turn signal is on, indicating that the meter is trying to register a RMS reading.

Conclusion: The green line (left turn/brake)from the front of the chassis is "dead"?

Question: Does anyone have any suggestions on what I might look at next. I can't trace the Green/Yellow lines further since they disappear into a large wire bundle that goes forward just past the rear axel.

genesimmons · 10-19-2012, 02:09 PM

most likely bad turn signal switch, had similar problem on my e350.i think it was left turn signals would not work and and when put the brakes on and turn signals at same time park lights would blink also cruise would not work. replaced switch in coloum and all works as it should

Murf2u · 10-22-2012, 08:11 AM

I don't know if the Econoline chassis is the same as the F-series wiring, but I'd check first the fuses, they have multiple ones, one is a 'chassis lighting' circuit, one is the 'trailer lighting' circuit.

If someone plugged in a trailer, or the trailer wiring got pinched, and there was a short circuit the fuse would pop.

If the front light is flashing the switch is working.

If you are getting power through the running light circuit jumping into the right turn/brake circuit it tells me you have some corrosion or something causing a partial (low conductivity, or high resistance) short circuit.

If you live in an area where winter conditions cause corrosion I'd start with the trailer wiring, especially if there's a trailer wiring plug.

Sandunagen · 10-22-2012, 10:32 PM

It is not the turn signal switch. Had same problem with mine and shop told me to change switch but it wasnt it. Check fuses in panel under hood, there is a fuse for left and a fuse for right side blinker and tail lights.