Repeatedly Blown Tail Light Fuse

RJV

Active member
I've owned my 2006 2500 for about 8 months now. Approximately 4 months ago as I was leaving work the van wouldn't shift out of park. Thanks to info on the forum I was able to use the pencil/pen override trick and got the van home safely--which was lucky because I later realized I'd driven 20 miles without tail lights. Once home, I further searched the forum and was relieved and happy to diagnose the problem simply as a blown tail light fuse. I didn't think much of it, I've had fuses in other vehicles blow before, replaced, and no further issues. That was the case for the past 3 months. Unfortunately, in the last month the same fuse has blown 3 or 4 other times. I'm guessing that there is a short in a wire somewhere, possibly a bad connection or a spot where the wire insulation has worn through. I've removed the tail light assembly from the inside of the van and checked that area for anything that looked suspicious but didn't find anything. I'm not exactly sure how the wiring runs through the van, but I've converted mine to an RV and the interior ceiling and walls are now fully covered--so removing the wall coverings is not really a good option. Has anyone else had the same issue or anything similar? Any advice to locate the problem? Thanks!
 
take a look at the rear light assemblies and where the wiring harness goes into each. look at the plastic bulb holders and look for signs of melting or damage or signs of a chaffed wire...this is a an easy place to start. You might employ a voltmeter check check for shorts to ground when doing a wire harness wiggle test too.
 

thinice

2005 tall 140WB 160K
Like Vic says, one of my boards had a slight bend, caused some arching. Try examining assembly in the dark while someone runs through the lighting sequences. Didn't notice the ever so small arching until I looked at it at night.
 

Goofy foot

sliding left...
Your van is 11 years old. I recommend taking your time and thoroughly cleaning and examining your rear tail light assemblies. Remove all bulbs and clean all contacts. Look to see if any new accessory has been spliced in to the feed wires in the assembly wells. Check all applicable grounding points(underneath back bumper area,etc.). Check the center high brakelight in the same manner. Hopefully your conversion didnt cover up the 2 access holes that allow you to remove the high center brakelight lens. If it did, I would create an access port there.
 

RJV

Active member
Thanks for all the input. I worked on it a bit yesterday. Started by checking the ground points(all good) and then with the drivers side tail light assembly. Basically I pulled it out to examine it and before I even removed the bulbs or anything else I started the van, all was good--until I hit the brake pedal and the fuse blew. So unless it's a coincidence, it's something with the drivers brake lights. From there I checked all the bulbs, connections, and contacts, etc. Everything was super clean, nothing looked out of the ordinary but I did clean them up a bit for good measure. Put in a new fuse and it too blew as soon as I hit the brake pedal. From there I disconnected the assembly all together. My thinking was that by disconnecting altogether, if the problem was with the circuit board/assembly or anything with the light bulbs, the short would not occur when the brake pedal was engaged and and the fuse would be fine. Unfortunately, the fuse did blow. So unless I am missing something, it's a wiring issue with the rear drivers side brake lights--and my guess is that it's something close enough to the actual assembly that when I removed the assembly, it disturbed the location of the problem enough to make the fuse blow. So from there I removed as much of the black cloth tape wrapped around the group of wires to see if there was anything unusual. Unfortunately there was nothing that I could see. At this point the only thing I saw that I didn't like was that the wires going into the multi pin connector which plugs into the light assembly were bent at about a 90 degree angle right where they entered the connector. I mean, that shouldn't be an issue, it's not like the wire is going to break by being bend, but in a last ditch effort I straightened them out. I was expecting that the fuse would blow again, but this time it was fine. I ran a few errands after that and it's been fine. I'm not convinced that anything I did fixed the issue, but I was happy that I can at least drive it with working brake lights for the time being. Due to the build on the inside of the van I can't really go over every inch of wiring. So I guess now I just wait and see if it happens again.
 

autostaretx

Erratic Member
I know you must have, but your description didn't seem to include the test of unplugging the connector from the lamp unit and then stepping on the brakes.
If the fuse still blew, it's the wiring/connector.
If the fuse didn't blow, that points at the lamp unit (although, as your current experience shows: it could be the wiring at the connector).
And, also as your experience shows, merely the act of unplugging/re-plugging the connector might have accidentally "fixed" it.

Oh, the joys of intermittents....
--dick
 

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