tail light electrical gremlin

[natejgreene9871]

I've been dealing with a tail light issue on and off for about a year now and I can't figure it out.

It is intermittent, happens about about once a month, no rhyme or reason. Goes away on its own but comes back.

On the drivers side tail light - the red running light will quit working ( blinker unaffected). i'll get the warning light on my dash.



i've tried swapping in a different tail light housing, i've also cleaned the ground cables where they all screw to the body around the antenna motor. Didn't fix it. This is a clean car, no corrosion or rust.

Last time it happened, I used a multimeter on the pins of the tail light plug and I was not getting power at the pins. So it is something upstream in the wiring.

What other body grounds am I missing here? Seems like a corroded connection I just cant find it.

 

[gsxr]

Is it the "corner" marker bulb? If so, the bulb holder is notoriously weak... bad design. Inspect closely if it's that bulb.

 

[vanwiek]

Maybe a failure of the exterior lamp monitor module? Mine developed hairline cracks in some of the solder joints.

 

[natejgreene9871]

Is it the "corner" marker bulb? If so, the bulb holder is notoriously weak... bad design. Inspect closely if it's that bulb.

I have traced it back to the electrical plug and I’m not getting power at the pins. It’s not the light housing.

 

[natejgreene9871]

Maybe a failure of the exterior lamp monitor module? Mine developed hairline cracks in some of the solder joints.

Where is this located? Under rear seat?

 

[vanwiek]

Where is this located? Under rear seat?

It’s located in the fuse box. You have to remove the complete top cover, not just the part that clips on and off to access the fuses.

 

[duuder]

i had this issue a little while ago, it was my fuse

 

[natejgreene9871]

I fixed it! @vanwiek was right on the money. I removed the lamp module from the fuse box and took it apart.

Upon close examination with a magnifying glass 3 or 4 of the larger solder joints had cracks in them. I reflowed all the larger joints with a soldiering iron and put it back together. East fix, took about an hour.

 

[duuder]

Wow nice!! I may have extra modules if anyone needs gratis, I got it from a forum member to try and solve the tail light issue I had before I realized it was the fuse

 

[natejgreene9871]

Wow nice!! I may have extra modules if anyone needs gratis, I got it from a forum member to try and solve the tail light issue I had before I realized it was the fuse

Thankfully these seem to be very repairable. Nice big pcb’s

 

[vanwiek]

I fixed it! @vanwiek was right on the money. I removed the lamp module from the fuse box and took it apart.

Upon close examination with a magnifying glass 3 or 4 of the larger solder joints had cracks in them. I reflowed all the larger joints with a soldiering iron and put it back together. East fix, took about an hour.

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I’m glad I was able to help!

 

[natejgreene9871]

So the story continues. The warning light came back again after a week, but this time it was only when the brake pedal was depressed.

I took the tail light housing apart and there was some corrosion on the contact bars. I already cleaned this up about 6 months ago but I guess it came back.

I made a slight modification, soldered some wires for redundancy. This housing isn't a great design, especially in a humid trunk.

Tail lights are a lot brighter now! No more warning light. Hopefully this will finally put this issue to rest. I think both the light housings and the module were causing issues.