turn signal lights up when braking help

rossco

New member
I recently purchased my own 2005 Dodge Sprinter 2500.

When I press the brakes the right-side turn signal illuminates. It doesn't flash it just lights up.

If I use the turn signal it works fine until I brake, as soon as I hit the brakes all three right-side lights stay lit, no flashing.

None of the lights are burned out. I just replaced the back right brake light bulb.

Any help trouble shooting this would be very helpful as I just purchased and I am not familiar with the sprinter layout yet.

p.s. the left side works great
 

AddicksAir

New member
Did you have the problem before you changed the brake light bulb?

If not, make sure the new bulb matches the old bulb or move the new bulb to the other
side and see if the problem follow the bulb.
 

rossco

New member
I had the problem before changing the rear bulb. At first I thought it was the Van's way of telling me the light was burnt out.

So i put the new rear bulb in after problem started with no change
 

AddicksAir

New member
I had a similar problem a couple of years ago. Can't remember, but there was an
issue with the bulb. Try moving the known good bulb from the other side to see if
the problem is still there.
 

rossco

New member
Cool, I'll try that tomorrow, thank you that was really fast!

I'll report back if it's that simple of a fix... i sure hope so
 

ifixsprinters

New member
Does your van have a trailer harness? I have ran into many aftermarket trailer light wiring problems because of people not using a trailer lighting module.
 

rossco

New member
Yes, there is a basic trailer harness. 3 female and 1 male prong I think, not looking at it (best way I know to describe it).

Should I try cleaning the connections or something?
 

ifixsprinters

New member
look under the left rear of the van next to the spare tire and see if someone has installed an aftermarket trailer harness. because sprinter has individual turn and brake lamp and trailers (at least in the US) use the same circuit and bulb for turn/brake. Sprinters owners install a trailer lighting module (if tow package isn't factory) to keep the turn and brake lights from feeding back through each other. the box may be bad and or you could have water intrusion into to harness that has been spliced into. more than likely the latter.
 

autostaretx

Erratic Member
Broken ground wires can also cause symptoms like this... the brake light current goes through the turn signal bulb to reach ground (perhaps on the other light fixture).

--dick
 

cedarsanctum

re: Member
+1 on Dick's suggestion. It might also be just a bad ground connection that looks good, and not have any broken wires. Check where the ground leads connect to the body.
 

220629

Well-known member
I had a similar problem a couple of years ago. Can't remember, but there was an
issue with the bulb. Try moving the known good bulb from the other side to see if
the problem is still there.
I always agree with the "first check the last thing done" theory. :professor: Especially check that you didn't loosen the connector that goes to the lamp assembly while changing that lamp. Other than that I'll chime in with the bad ground people. FWIW.

There's some info in this post about what goes where in the T1N tail light assembly traces. Good luck. vic

https://sprinter-source.com/forums/showpost.php?p=99430&postcount=122
 
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