Side brake lights don't work, top light does

[6716]

Top brake light good. Running lights good, flashers good, backup lamps good. New lenses/circuit boards within 3 months. New LED lamps within 3 months.

Engine compartment fuse is good. Back seat fuse is good. Trailer brake lights are good. Wires into circuit boards look good. Circuit boards look good/no damage.

Did replace the flasher module with the new LEDs, and swapped in a donor steering column, a couple months ago, and swapped back in the turn signal stalk from the original column.

Checked operation on the tail lights after the lens/LED swap. Did I check after the flasher swap? Maybe? Should that part matter? Probably did not check tail lights after the steering column swap.

I don't know where in there they went out, just that they don't work now.

Watched some videos, didn't really get anywhere with those.

Thoughts?

 

[Redbeard]

I would start using a test light at the bulb socket. Make sure you have a good ground from your test light to a "clean" ground. Let's see if there is voltage at the bulb socket along with enough current to light the test bulb. If it is there it is likely the bulbs have burnt out. Or the ground has been lost. Personally I have not had good luck with the LED light bulbs lasting more than a few months, yet others on these boards have much better service from them. Or the circuit board died. Do your backup lights work? The reason I ask to see if the ground might be giving you this problem since the ground works with all the lights back there (backup, turn, & running lights). Maybe just pick up some new bulbs and try them. And I say this because the elderly neighbor behind me had a porch light fixture go out this week. I removed the old bulb, put in a new bulb she handed me and guess what did not work. I disassembled the fixture and no wiring problems were found, so I took the new bulb to my house I put it in a known working lamp - and the new bulb did not illuminate! So I got a working bulb from my stash, screwed it in and now her porch light works. Start with the simple first. See if you have voltage at the bulbs socket currently.

 

[christo829]

Something else to consider is the brake switch. The third (or center mount high) brake light does not run through the same contacts as the regular side lamps.

Don't rule out the circuit boards going bad. When I first got my TB it had brake light issues, so I replaced the circuit boards. I recently replaced my tail lenses because the inspection station pointed out that they were different colors, and the one I believe was original looked orange. The previous owner must have replaced one at some point, and the inspectors suggested that the color difference was enough that it might get me pulled over. So I bought full assemblies, lens and circuit board. Not more than a month later, the brake lamps failed. All the other lights worked. Checked the brake light switch because I figured the boards were new enough to not have failed, and it was operating properly. Both bulbs were good as well. Swapped the circuit boards out of the old tails in to the new lenses, and they've been working fine since.

Good Luck!

Chris

 

[TJBaker57]

Something else to consider is the brake switch. The third (or center mount high) brake light does not run through the same contacts as the regular side lamps.

I checked wiring diagrams for 2002, 2004, 2006, 2007. All show the CHMSL uses the same single contacts in the brake switch, splitting out in the rear fuseblock. After the split there are separate fuses for the rear stop lamps and the CHMSL.

 

[christo829]

SMH... Must have gotten that mixed up with diagnosing the interlock circuit or something. Apologies for the error!

 

[Sparky]

Just to rule it out, stick a regular bulb in just to make sure nothing is whack with the LEDs.

 

[budwich]

I checked wiring diagrams for 2002, 2004, 2006, 2007. All show the CHMSL uses the same single contacts in the brake switch, splitting out in the rear fuseblock. After the split there are separate fuses for the rear stop lamps and the CHMSL.

that would be the place to check for voltage AND ensure that you check the right fuse.

 

[6716]

Looks like it's the LED bulb, but not the way I thought.

I put an incandescent in -- works like it should, running light plus brighter brake light.

I started flipping the LED, and one way it's a brake light, and the other way it's a running light, but it's never both.

It looks like a standard Sylvania 3157 LED has polarity. Like in the flasher/turn signal position, it will either work or not depending on which way you have it. If it doesn't work, pull it out and flip it, and it will work.

There is a more expensive Sylvania 3157 that says it has dual polarity, but I don't know if that one will solve the problem or not. At the very least it advertises that it will work no matter which way you put it in the reverse light spot or the flasher spot. But also, it doesn't advertise itself as a brake light/running light.

I think if I had paid really close attention to how many of the LED pads were lit up on the lamp depending on whether it was in brake light polarity or running lamp polarity, I might be able to guess if the dual polarity one would work as a brake/running light.

Anyway, instead I ordered a dual intensity LED from blamazon. It arrives tomorrow. At $10 it's half as much as the Sylvanias but it has solid reviews.

 

[Blckshdw]

I wonder if the Sylvania was setup as SRCK instead of standard?

I got a couple sets of these JDM Astar bulbs in red and white after I broke my LED tail lights back in 2019 and had to put the stock housings back in. They've been going strong ever since.