Left Rear Brake Light and Battery Needle Fluctuating

[Sniperdyer]

It seems I have a short( I think) in the left rear tail light and high brake light. My battery needle in dash constantly fluctuates a lot and I noticed when that happens the left bulb is out. Then after some time ( sometimes days later ) the bulb turns on and the battery needle settles down. Is this a short ? I've replaced the bulb and individual socket and still have the issue. Would you guys have any advice you can pass along to me.
Anyone know where I can find the wires for the left side and high mount brake bulbs? I recall seeing a wiring harness in rear left side in cargo but the harness looks fine

 

[ChildIdenticant]

When the "bulb is out", is it just the running light?Is it also dark if left turn signal/hazard/brake is selected?
I assume your CHMSL issue is unrelated and never turns on. In which case first thing to do, if you have put good bulbs in ( good brake switch is assumed), is remove the housing, and with brake pressed. test the harness connector with multimeter as the seats for the bulbs can be the issue.

 

[J_C]

In addition to the voltage test that CI proposed, I'd also measure resistance between the bulb socket ground and chassis ground in case it has a bad ground. A bad (high resistance) ground can still look like 12V with no load (bulb) in the socket. You could also measure resistance between the power and ground contacts in the socket, and check resistance between the positive bulb socket contact and the next thing upstream... parking lamp relay? I have same question as CI, is it the rear left parking lamp, and/or the brake light not working?

I can't think of a reason why that would be caused by same fault as your battery light flickering, I mean if you had bad power delivery or alternator on the way out and that's dropping voltage everywhere, you'd notice it other places besides just the left and center rear lights.

 

[Sniperdyer]

The weird thing is that the brake light, hazard and turn signals also go out. But then it works at times. I did change the sockets. I opened up the fuse panel and I started testing the fuses and some don't light up. I'm going to buy a fuse kit and replace the fuses. Are the ATC or ATM? Reason I ask if maybe mechanics in the pass swapped out and replaced incorrect fuses. Pictures attached.

 

[ChildIdenticant]

If the tail light/running light, brake/hazard/turn are all consistently effected at the same time, anything but a ground issue of the bulb housing would be unexpected. Can you confirm that the license plate lights are also effected at the same time? If so, the jumping voltmeter only when the issue present... I'm not seeing how that can happen stock and be related. thus...

...do you know if there was ever a lojack type system installed in the vehicle? Because , that was the place.

 

[Sniperdyer]

I swapped out all the fuses and the battery fluctuation stopped and is steady now. I had read that it could've been a dirty alternator fuse. I cleaned the fuse box also.