Tail lights and interior lighting not functioning

backwthemilk

backwthemilk

New Member
Original poster
Joined
Aug 3, 2024
Messages
6
Location
Fairplay, Colorado
Not sure what started the problem. I know that in some cars the tail lights and interior lights are connected to work as a fail safe. Also the turn signals fail to light up when the headlight is turned on. The Courtesy Lighting and the speaker bar light work, but the gauge night lighting and gear selector light does not. the Check Engine light still works.

possible causes:
-I installed a new multifunction switch, but the hazard lights do not work, so it could be faulty which causes the illumination slider on the turn signal switch to not work.
-I replaced my receiver with one with Bluetooth functionality, but it does not have a input for the illumination cable, so the cable was left severed. But when the stereo is unplugged, the lights still do not work
-Drove through a storm with a windjammer, causing the back of the jeep to be wet, so possible damage to the taillight wiring, but the brake/reverse lights still work fine.

I bought this wrangler in February, and I've been sorting out the electrical issues it came with one by one, but I'm stuck on this one.
I can't pinpoint exactly when the issue starting happening, as I just noticed it.
 
Last edited:
Verify the grounding connections on passenger and drivers side near the back of the headlights on the radiator support are clean and tight.
Since you already replaced the MFS; you should inspect the wiring harness and connector for signs of overheating and oxidation on terminals.
 
backwthemilk said:
Not sure what started the problem. I know that in some cars the tail lights and interior lights are connected to work as a fail safe. Also the turn signals fail to light up when the headlight is turned on. The Courtesy Lighting and the speaker bar light work, but the gauge night lighting and gear selector light does not. the Check Engine light still works.

possible causes:
-I installed a new multifunction switch, but the hazard lights do not work, so it could be faulty which causes the illumination slider on the turn signal switch to not work.
-I replaced my receiver with one with Bluetooth functionality, but it does not have a input for the illumination cable, so the cable was left severed. But when the stereo is unplugged, the lights still do not work
-Drove through a storm with a windjammer, causing the back of the jeep to be wet, so possible damage to the taillight wiring, but the brake/reverse lights still work fine.

I bought this wrangler in February, and I've been sorting out the electrical issues it came with one by one, but I'm stuck on this one.
I can't pinpoint exactly when the issue starting happening, as I just noticed it.
Click to expand...

Check the fuses the tail light fuse powers the illumination fuse.
 
NskLJ said:
Check the fuses the tail light fuse powers the illumination fuse.
Click to expand...

NskLJ said:
Fuse 7 under the hood powers multi function switch
Click to expand...

#7 is fine, and when the illumination slider on the turn signal switch is at the highest setting, the interior lighting EXCEPT for the blue gauge and gear selector light work. So the multifunction switch may not be the problem, not to mention the turn signal and wiper switch both work.
 
Fuse #1 is on the same power source as fuse #2 which is for the brake lamps. Do they work? If they do, with fuse #1 being good you should have power at the multifunction switch for the tail lights.

If the brake lamps don't work I'll need to know what model year you have to be able to tell you which fuse in the under hood Power Distribution Center (PDC) supplies those two fuses.
 
jonny jeep said:
Fuse #1 is on the same power source as fuse #2 which is for the brake lamps. Do they work? If they do, with fuse #1 being good you should have power at the multifunction switch for the tail lights.

If the brake lamps don't work I'll need to know what model year you have to be able to tell you which fuse in the under hood Power Distribution Center (PDC) supplies those two fuses.
Click to expand...
the brake lamps work, and the fuses work, i checked with a multimeter.
 
Issue Resolved, make sure you order the correct multi-function switch, I ordered a new switch from ExtremeTerrain, don't buy from Amazon, even if it looks identical.
 
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