Wrangler Rear Taillight Question

[ccarm]

I have an 05' LJ, and recently the rear passenger tail light was ripped off (think hammer to the glass, and wires ripped in two. Well the business that was reaponsible for the damage ordered a new unit, and I got it earlier today. I installed the light, and turned on the hazard lights to see how well it worked.

As I was looking at the two tail lights, the passenger (new) one was at full brightness, but the driver (old and not broken) side tail light was really weak. I reset the computer (unplugged the battery, waited a minute, and reconnected it), but to no avail. Has anyone else experienced this or have something that I could do to fix it? Are tail lights like headlights where they recommend that you install two new ones at the same time? Any help welcome--electrical systems always seem to be a headache.

 

[outinthewoods]

could it just be two different bulbs, hence different brightness? yes, always do bulbs at the same time, as far as I know.

 

[67390FE]

A rear light has a parking lamp and a stop light filament each in one bulb. I would start by checking that the wires are connected correctly. If I remember correctly, my '03 Rubi has the brake light with a black and yellow wire and the park lamp is a brown and red wire.

 

[bob91yj]

Swap the bulbs side to side, see what happens.

 

[ccarm]

Flipped the bulbs...no difference. It's not the bulbs, but I don't know why the computer would send two different wattages to the lights on purpose. Guess I'll have to get the famed voltmeter out of the toolkit. But, I'm tempted to do the "just wait for a while and see if it fixes itself first" trick.

 

[outinthewoods]

My JK does A LOT of weird electrical things...


for example I went wheeling a couple days ago, the sensor for the coolant temp went crazy, then the airbag warning was on, and the electronic speed control warning.

then they all went off in a day or two. Except now my cruise control doesn't work.

I know this doesn't help you. sorry bout that

 

[wjeeper]

It's not the bulbs, but I don't know why the computer would send two different wattages to the lights on purpose.

I will tell you that the computer (most likely) has nothing to do with the taillights. The computer primary job is monitor the powertrain and emissions controls. The chassis harness and powertrain harnesses are generally separate entities in vehicles

Looks like swapping the bulbs from side to side didn't seem help. Next step i would take is checking the ground to the dimmer taillight. I am not 100% sure but I think the light is grounded through the mounting bolts some corrosion on the bolts could be the culprit. Sometimes if you buy a cheap Chinese replacement light will be brighter (and usually more pink) than an OE taillight.

Do the taillights both turn on when the running lights are going? Does the dimmer of the two taillights brighten when the running lights are on and you press the brakes? as 67390FE is saying the rear light is a dual filament. Are both filaments doing their job?

A rear light has a parking lamp and a stop light filament each in one bulb. I would start by checking that the wires are connected correctly. If I remember correctly, my '03 Rubi has the brake light with a black and yellow wire and the park lamp is a brown and red wire.

Not trying to come off as a know it all but owning a few wranglers I have spent enough time messing around with the lights from time to time........sometimes the "wait and see if it fixes itself method" actually does work :elkgrin:

 

[Overlandexpeditionspecial]

Are they brighter with the taillight lense off? I replaced one the other day and the older was significantly darker (guessed aging).

The other thing I have come across with the front turn signals, is actually the tabs (can't remember if they were on the bulb or in the socket now, but they get soft and spread, so just bend them back with some needle nose to tighten the connection.) Of course if that bulb on the back is actually the two little bumps on the bottom, this wouldn't apply but you might also try some electrical cleaner on the connections.

Or just view it as a good time to sell both those lights on ebay and buy some fancy new LEDs instead:elkgrin:

 

[orangeTJ]

Flipped the bulbs...no difference. It's not the bulbs, but I don't know why the computer would send two different wattages to the lights on purpose.

The computer doesn't send out "wattages" to the bulbs.

Wattage is something that the lamp produces based on the voltage it gets.

One of the wires might have a loose connection, maybe a bad ground. or there's a problem with something being loose in the tail light assembly.

 

[alosix]

The computer doesn't send out "wattages" to the bulbs.

Wattage is something that the lamp produces based on the voltage it gets.

One of the wires might have a loose connection, maybe a bad ground. or there's a problem with something being loose in the tail light assembly.

On a JK (or any other Chrysler CANBus vehicle) the FCM controls most of the lighting (though nothing really more than an on off).

An 05 LJ is old school. Like others have said, check connections, check grounds.

bulb sockets, light connectors. I think the ground is just to the body there, so even pulling the other light off and cleaning the contacts might help a bit.

Jason

 

[ccarm]

Alright Ladies and gentlemen...the problem has been officially fixed. I went with the "just wait around and maybe it'll fix itself" method for about a week or so to no avail. SO I finally went back through and checked all of my ground points. When I had installed a set of metal tail light euro guards, the hardware that it came with had some silicone washers. Well, I took those off, and replaced the hardware with some stainless bolts that fit much better. Popped the lights back on, and voila! the taillights were working perfectly. It was just a grounding problem that I was losing with those stupid silicone washers.

 

[thejafe]

Alright Ladies and gentlemen...the problem has been officially fixed.

Oh well, I was gonna suggest a set of ORO LiteDOT's like the ones I installed on my rig last summer :sombrero: :