Anyone run into this problem? Right turn signal works fine, but when the left signal is activated both of the back lights flash. Front signals work right, it's just the back lights that flash wrong.

I messed around with the fuses and they're all in there right and it didn't fix anything. So I'm guessing it's something in the steering column?

If anyone has had a similar problem I'd love to hear how you fixed it or if anyone has some input I would really appreciate some help. Thanks!

 

This happens fairly often on chevy trucks and certain models of Jeep Cherokee but never heard of it happening on a Dodge truck. At any rate though you don't mention the year and model of van but generally, listed in order of likelihood:

1. Wrong bulb installed in tail light socket (can cause a short between light & blinker circuit)

2. Bad flasher relay, located on fuse panel on late model Dodge Ram vans and trucks

3. Bad turn signal switch

Oh also if you have any kind of trailer lighting harness installed I'd probably check that out first. These are often wired incorrectly and/or short out due to moisture, dirt, or abuse.

 

Thanks so much for the reply It's a 2003 B3500. Hopefully it's just a wrong bulb. There is a trailer hitch and some wiring down underneath, I'll make sure to check that out.

 

I checked all the bulbs and they're good but I discovered a new problem. The right brake signal isn't working. The bulb works, but it won't light up when the brakes are hit. It lights up when the flashers are on and when the running lights are on, but just not for braking.

I checked out the trailer harness and there was some weird ****, someone had spliced into the wiring to add on a different trailer hook up. So there were two trailer wiring hook ups. I removed the second one and taped the wires up so everything should be back to factory, but the problem with the lights is still happening.

Could a bad flasher switch or relay also cause problems with the signal sent to the brake lights?

 

The trailer wiring is always an issue. Those wire taps one uses to splice into a circuit usually breaks a lot of stranding on the wire which was tapped. Soon thereafter corrosion sets in and it is just a matter of time. I had to spend a few hours cleaning up what the previous owner botched in a rush to do what ever he needed to do. I was getting only 9 volts to my passenger side brake light as the wire was so degraded where it was "tapped'

The taillights ground connections are likely the issue. When current has to seek a different path to ground strange things happen which confound logic. I am not familiar with a 2003 but make sure the wires for the reverse bulb are clean and tight. My'89 has the ground for the taillight assembly integral with the whole circuit. Remove the reverse bulb holder and my lights will not work properly and will do screwy things like you mention.

 

All the wire connections appear to be good. They're all snug in there and doesn't look like anything is corroded.

One or two of the wires underneath that were spliced into looked like they have gotten hot at some point, but they didn't look real bad.

It seems real strange to me that the passenger side bulb would come on for the right turn signal but not the right brake when the signal comes along the same wire.

 

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