Ronald Maddox

I have a 99 gc Laredo and can't figure out what is causing the passenger side tail light to not get power. I initially started with a new bulb, then fuse before I replaced the light socket (not sure what the actual name of the part where the light goes in is called) and after those all failed to fix it I used my test light at the plug to see if I'm getting any power to it. I was able to confirm that it's not getting power but don't know what my next steps should be since most of my mechanic training was obtained by watching YouTube and reading these forums. Any help would be greatly appreciated

Noah911

The tailights normally turn on and stay on whenever you have the headlights switched on.

The brake lights of course normally only come on whenever you have the brake pedal pushed down...

Are you saying both, the tailight and the brake light, neither one of these works on the passenger side?

dave1123

Would that be the circuit board, Noah?

Noah911

What circuit board??? I do not see a circuit board..

I am just kidding. I know of it. There is a circuit board hidden inside of the tailight housing assemblies that is nearly impossible to replace without breaking the housings all apart.

I forget what I was thinking for on this case? I had a good thought process on what it may be, depending on the response received from the above question I presented. I looked up a thing or two and applied some knowledge to what I found out specific to these Jeeps and their tail/brake lights. I do not really remember it anymore right now.

The tail lights, brake lights, headlights, and running lights issues on most vehicles can actually be very difficult to comprehend when things are acting up and going wrong like this.. It confuses me sometimes with these types of problems.

I think my process was to first try and figure out wether or not there really was actually no power getting to the tail/brake light as how it was said... and then to go from there. I would have to look it up again in order to remember where it was I was going from that point in order to be sure of it though.

dt750

from what I read, it's just the right tail light not working. does that mean non of the lights (brake, turn signal, back up lights)?

Noah911

I think so too. 'Tailight'.. that means to me it is the tail light only, and not also the brake light function of the bulb... A dual-filiment bulb. So, one bulb for both of those functions... Also, he said he replaced a "socket" (singular) and not sockets (plural). If it were the whole tailight assembly not working it would require all three socketS (plural) to try and change-out...

So, it is not the whole tailight housing assembly being out with no lights on that side..

But still.. is it just the tailight? Or, is it both, the tailight and the brake light not working? The same bulb and the same socket for both of these functions...

It could likely be the contacts of the housing how the heat melts to distort the actual housing. This can turn down the ground or other contacts, and stops contact from occuring to allow the bulb to function. But, if there truly is no power getting to the location from the harness side?

It could be the internal circuit board of the housing too, depending on if power is actually getting up to it from on the harness side...

A good way to check is to just switch sides with the assemblies. They will plug up that way, and if the problem follows the assembly... Well, that explains things doesn't it. Then, it would be likely the circuit board or the contacts of the socket-thing (they are not traditional bulb sockets, as they are actually on a circuit board...).

dave1123

Yes, if it's just the bulb holder (socket) you can switch the reverse light holder to the tail light position and it should function simply because that bulb doesn't get as hot as the brakelight does, especially after you sit in traffic with your foot constantly on the brake. Heat tends to melt the plastic and weaken the bulb contacts.

Ronald Maddox

yeah. Neither of them work. I tested with a probe the plug right behind tail light housing and it isn't getting power

dt750

ok, no power to the plug, do you have a tow hitch under it, if so it could be the wiring connection. just to be clear you tried it with the vehicle in reverse, and had somebody hit the brakes, etc. while you tested the plug for the lights and got no power.

Noah911

Gotcha. I think I would want to go beyond the plug to test all of the wires next. The black wire is the ground, black/yellow is for the tail light power, and the white/brown wire is power for the brake lights. At minimum this will rule out the plug itself as having gone bad. It will also verify a second time for you that it is definitely not the tailight housing contacts or the circuit board in the housing to be sure.

It sounds like you have already checked and changed out the bottom left 15 amp #23 fuse. But, this should effect both sides anyway though....

From there you can test further downstream if the wires right behind the housing assembly is not testing proper. The next spot to check for the brake light is at the brake light switch at the brake pedal. Power comes from the fuse to here, and this is where power leads back from here to the brake lights. I would have to double check on it to be 100% sure.. but, I think it is the pink wire with a blue tracer is the wire to check at the brake light switch. It will tell you something.. I am just not sure if it is the feeder wire for the brake switch? Or, if it is the feeder wire to the brake lights leaving from the switch? Still, this should effect both sides as well to shut down both, the passenger and the driver side brake lights....

There are a lot of things involved for the brakes like the ABS and Traction Control System with all of their relays and switches and such to be aware of.. Still, most of the problems with these things will also effect both sides....

The wiring should have the power wires going to probably the center tail/brake light first. From there it probably branches off to the other two lights. It sounds like there may be an open or problem like such from at this point where it branches to the three lights back there? You may have to remove the paneling on the backside of the Jeep to follow the wires from behind the tailights assembly housing from the harness side following them.. and checking them to see where the power stops.