Right Rear Brake Light/Blinker Inoperable

[LJ_Rubi]

Hey, folks, hope all is well. First time poster and a new owner of a 2005 LJ. Looking forward to the mindshare here.

I've searched the forum ad nauseam but I have yet to find an "electrical/lighting" situation like the one I have on my hands, so I am hopeful making yet another post about faulty lights is permissible and I can get some guidance and not flamed. Thanks in advance for your time and opinions..

Last night as I was driving home when I turned on my Right blinker it started to flash incredibly fast--so when I got home I checked the bulbs on the Right side of the vehicle and noticed that the Right side marker bulb was fried. This morning I went up to the local store and picked up some new bulbs, installed them on both sides, but I still had the super fast Right turn signal flash when activated. So I headed to the back of the vehicle and noticed that the Right rear light wasn't blinking at all. Went back to the store, got some new lights, installed them on both sides. When I tested the turn signal again I got nothing on the right side. However, when I turned my lights on...the Right rear light came on, but still wouldn't flash. The other unkown in the equation is that the Right rear light does not work (brighten up) when the brake pedal is applied. The Left light works, the center brake light that is barely visible over the spare tire works, but the Right light doesn't work. These are all standard bulbs....no LEDs (yet). In sum, this is how it breaks down...

Accessory Power On

Left Turn Signal Activated:
All Left Turn Signals work properly and the the Turn Signal Indicator blinks at the normal cadence

Right Turn Signal Activate:
Front Right Turn Signals work properly though they flash at a much higher cadence, Rear Turn Signal does NOT work

Brake Pedal Depressed:
Left Brake Light works properly
Center Brake Light works properly
Right Brake Light does NOT work properly

Gear in Reverse:
Left Reverse Light Works Properly
Right Reverse Light Works Properly

Lights Turned ON (while in Acc Mode):
Left Rear Light Works Properly
Right Rear Light Works Properly

Hazards Activated:
All Left Side Lights Work Properly
Front Right Lights Work Properly, Right Rear Light does NOT flash.

Any idea what is going on here or where I should start the troubleshooting? All bulbs are new and this just started happening (decent amount of rainfall this past week) last night. I've got probably 400 miles under my belt without issue. Really appreciate the help....I know this is like shooting fish in a barrel, but hopefully by looking at the break down of when it does and doesn't work I can eliminate at least a few things. Thanks!

 

[DuckNut]

Sounds like corrosion on one of the bulb connectors. Take the bulb out and scratch the connectors at the bottom. Also inspect the entire socket.

 

[B1Toad]

Without looking at the wiring diagrams for your 2005 I am pretty sure the brake light/turn signal power goes through the multifunction switch. There are 2 filaments in the bulb, one for park/tail and a brighter one for brake/signal/flasher. If the connector is good per DuckNut's suggestion next you will need to start following the circuit and checking for power.

Best to go to the resource section and find your factory service manual, go to the wiring diagrams and print out the ones that include the rear lighting. Then look up the locations of all the splice and connector locations for that circuit. Highlight the circuit path and mark the locations of the splices and connectors on the diagram Now you can take that out to the Jeep and follow the wire path and check at various points to see where power is present and where it is not which will help you pinpoint where it is lost.

 

[LJ_Rubi]

Without looking at the wiring diagrams for your 2005 I am pretty sure the brake light/turn signal power goes through the multifunction switch. There are 2 filaments in the bulb, one for park/tail and a brighter one for brake/signal/flasher. If the connector is good per DuckNut's suggestion next you will need to start following the circuit and checking for power.

Best to go to the resource section and find your factory service manual, go to the wiring diagrams and print out the ones that include the rear lighting. Then look up the locations of all the splice and connector locations for that circuit. Highlight the circuit path and mark the locations of the splices and connectors on the diagram Now you can take that out to the Jeep and follow the wire path and check at various points to see where power is present and where it is not which will help you pinpoint where it is lost.

Thanks

Sounds like corrosion on one of the bulb connectors. Take the bulb out and scratch the connectors at the bottom. Also inspect the entire socket.

I'll do it in the morning, thanks!

 

[LJ_Rubi]

Without looking at the wiring diagrams for your 2005 I am pretty sure the brake light/turn signal power goes through the multifunction switch. There are 2 filaments in the bulb, one for park/tail and a brighter one for brake/signal/flasher. If the connector is good per DuckNut's suggestion next you will need to start following the circuit and checking for power.

Best to go to the resource section and find your factory service manual, go to the wiring diagrams and print out the ones that include the rear lighting. Then look up the locations of all the splice and connector locations for that circuit. Highlight the circuit path and mark the locations of the splices and connectors on the diagram Now you can take that out to the Jeep and follow the wire path and check at various points to see where power is present and where it is not which will help you pinpoint where it is lost.

Well that doesn't sound fun. Before I go to that length, I'm going to purchase some LED bulbs with an LED Flasher Relay and see if it behaves the same way. If it doesn't have power it doesn't have power though, so I'll need to follow your suggestion and isolate the area that is causing me this headache.

I just realized that I didn't replace the lenses on the rear lights when I was performing my various tests....and I read somewhere that the 4 screws act as a Ground. Will the lights perform the same with or without the lens? Thanks!

 

[B1Toad]

Well that doesn't sound fun. Before I go to that length, I'm going to purchase some LED bulbs with an LED Flasher Relay and see if it behaves the same way. If it doesn't have power it doesn't have power though, so I'll need to follow your suggestion and isolate the area that is causing me this headache.

I just realized that I didn't replace the lenses on the rear lights when I was performing my various tests....and I read somewhere that the 4 screws act as a Ground. Will the lights perform the same with or without the lens? Thanks!

The screws for the lens are isolated and have nothing to do with grounding.

 

[B1Toad]

Another though, if you have a trailer light connector follow it to where they connected it and inspect the wiring. The tail light wiring can be accessed by removing the plastic push nails and pulling down the plastic fender liner under the tail light.

 

[LJ_Rubi]

Another though, if you have a trailer light connector follow it to where they connected it and inspect the wiring. The tail light wiring can be accessed by removing the plastic push nails and pulling down the plastic fender liner under the tail light.

I do and I will, thanks!

 

[LJ_Rubi]

@B1Toad

The fuses checked out, cleaned the bulb connectors, bought all new LED bulbs with a LM470 Flasher Relay and installed those--which corrected the super fast blinking when the Right turn signal was engaged. The things that still didn't work were the Right brake light, Right Turn Signal, and the Right Flasher. I took the assembly off of the body and what you see attached is what I saw. I'm far from an expert here but I don't think whatever is going on is "normal"...but maybe it is? The one exposed cut and frayed Red cable probably needs to go somewhere....but I have no idea where to start.

Seriously considering just taking it to a shop and getting LED assemblies and be done with it. Any thoughts?

 

[B1Toad]

That's a diode kit that was installed for towing the Jeep behind a motorhome. I think your choices are to re-connect the wire that came undone or eliminate the diode kit completely.

 

[LJ_Rubi]

That's a diode kit that was installed for towing the Jeep behind a motorhome. I think your choices are to re-connect the wire that came undone or eliminate the diode kit completely.

I'm assuming that red wire that is cut connects to the one with the white plastic connector?

That's a diode kit that was installed for towing the Jeep behind a motorhome. I think your choices are to re-connect the wire that came undone or eliminate the diode kit completely.

BINGO! We are in business. Everything is working as it should after I removed that contraption and connected the wires with its mate. There was one wire that didnt have a home...and its still homeless, but once I put the three mounting bolts of the assembly back in to the body and grounded it they all fired up nicely. Lets just hope my twist nut connectors stay fastened as I didnt have much wire to play with. Thank you @B1Toad!!

 

[B1Toad]

I'm assuming that red wire that is cut connects to the one with the white plastic connector?


BINGO! We are in business. Everything is working as it should after I removed that contraption and connected the wires with its mate. There was one wire that didnt have a home...and its still homeless, but once I put the three mounting bolts of the assembly back in to the body and grounded it they all fired up nicely. Lets just hope my twist nut connectors stay fastened as I didnt have much wire to play with. Thank you @B1Toad!!

I wouldn't consider twist on wire nuts as a permanent fix on a vehicle that is subject to movement/vibration/weather. There are butt connectors and heat shrink or even solder seal butt connectors that work with a heat gun that will be better than wire nuts.

 

[LJ_Rubi]

That's a diode kit that was installed for towing the Jeep behind a motorhome. I think your choices are to re-connect the wire that came undone or eliminate the diode kit completely.

I'm assuming that red wire that is cut connects to the one with the white plastic connector?

I wouldn't consider twist on wire nuts as a permanent fix on a vehicle that is subject to movement/vibration/weather. There are butt connectors and heat shrink or even solder seal butt connectors that work with a heat gun that will be better than wire nuts.

It's all I had today..and I wasn't about to get out in traffic for something I was skeptical about. I'll get more appropriate connectors this week and tackle it next weekend. Thanks again

 

[B1Toad]

I'm assuming that red wire that is cut connects to the one with the white plastic connector?

Not sure, maybe the floating white connector is suppose to plug into the diode. You did say everything works now though? Do both reverse lights work?

There are probably 3 more diode modules on your Jeep. I believe this is the one you have: https://www.etrailer.com/Flat-Tow-W...M-154.html?hhyear=2005&hhmake=Jeep&hhmodel=TJ

 

[LJ_Rubi]

Not sure, maybe the floating white connector is suppose to plug into the diode. You did say everything works now though? Do both reverse lights work?

There are probably 3 more diode modules on your Jeep. I believe this is the one you have: https://www.etrailer.com/Flat-Tow-W...M-154.html?hhyear=2005&hhmake=Jeep&hhmodel=TJ

Well, that was short lived. I went to put some electrical tape around the twist nut connectors to get me through the week and then I tested everything out and now I've got both sides flashing when i out the turn signal on either side. I have no idea how to explain why it was perfect without tape and now its all out of whack. The one wire without a home is so dirty that I can't really make out what color it is, but I am going to look in the tech manual anyway.

 

[B1Toad]

You really should go back to the incandescent bulbs and the OEM flasher till you get this all sorted. Changing to LED doesn't always go seamless so get one thing working right before going to the next or you'll be going in circles.

 

[LJ_Rubi]

You really should go back to the incandescent bulbs and the OEM flasher till you get this all sorted. Changing to LED doesn't always go seamless so get one thing working right before going to the next or you'll be going in circles.

You are absolutely correct. I'm done playing with it today and I'll get around to it mid-week. I am expecting a different brand/model Flasher Relay in the mail so while the cluster is not pieced together I'll toss that in before I go back to the incandescent to troubleshoot. For some reason I think these twist nut connections may have something to do with it so ordering a Left and Right replacement assembly is crossing my mind (would like to keep it as stock as possible). Not sure what this one wire does, either....and I haven't been able to get under and trace where it ties into.

 

[LJ_Rubi]

You really should go back to the incandescent bulbs and the OEM flasher till you get this all sorted. Changing to LED doesn't always go seamless so get one thing working right before going to the next or you'll be going in circles.

@B1Toad

The front LED turn signal bulbs were the culprit. They were the first thing I swapped out and everything works as it should now....with those being the only incandescent bulbs in the patch. Thanks again for your help.

 

[B1Toad]

@B1Toad

The front LED turn signal bulbs were the culprit. They were the first thing I swapped out and everything works as it should now....with those being the only incandescent bulbs in the patch. Thanks again for your help.

There are some threads here on that, if I recall others have had issues with the front signals as well. I'm still all incandescent so no help there.