Electrical Issue-One tail light out

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Jukelemon

Jukelemon

10 Year 15 Year 20 Year
Joined
Dec 29, 2003
Threads
283
Messages
2,381
Location
Louisville, KY
Hi all.

I just noticed last night that my Driver's side tail light has issues.

The parking light/brake light does not work.

The bulb is fine and I even swapped in a new one. Reverse light works and the turn signal works.

Here is what is strange-I am not getting any voltage at the harness for the parking/brake light i.e. I pulled the tail light assembly off of the harness and tested for voltage on every function. All were fine except for the parking/brake.

The Pass side tail is perfect.

Any ideas?

Can the tail relay kill only one side if it is defective?

Thanks
 
I did not think that there was a fuse for each light. Pretty sure it is only one and the pass side, rear light all work fine.

Wiring is bone stock and has worked for, well, I guess 17 years ( :

I dont think it is a ground because the other bulbs share the same ground and they work fine.
 
Yeah, I dont think it is a bulb/socket issue. It is definitely a 12v source issue.

I say that because I am making these checks at the harness not at the assembly/sockets.

Sh-t. I hate tracking down this stuff.

It WAS working perfectly fine.
 
Please post your solution, if/when you receive one. My brother just bought his first rig (91 4Runner). He has the same issue--driver side brake light not working. We changed bulbs . No luck. (Then tested bulb on passenger side. Bulb was good.) We took off the passenger side brake light and tried it on the driver side. No luck. Everything else on driver side appears to be working (blinker/park light). We then pulled/checked fuses under hood. All appeared fine. I have been scouring the site YotaTech for answers. No luck. Now, I'm searching this site--and stumbled across what sounds like the same issue. Again, please let me know what you find. Also, we were not able to locate another fuse box. (My 96 & 98 4Runners had a fuse box under the dirver side interior. But, we found nothing. Is there another fuse box? Any info would be appreciated. (I'll continue to use the search feature for answers.) Thank you.
 
Hi, I will do that. I will be looking into it today after work.

Accoring to the layout, there is only one tail light circuit which means it just splits under the chassis i.e. goes to the Pass side first then branches to the Driver's side.

Everything looks good on the termination end i.e. sockets are OK, harness connector OK etc. Has to be a feed issue.

BUT....maybe not. We will see.

I will report back tonight.
 
Well, I have no clue..

I looked at the wiring in the back and there are no tears or burns. Everything is as should be.

And there are two circuits for the tail lights-one for each side. Not sure why.

Does anyone know if there is a relay for the tail light?

I even tested the brake light function and both lights work. WTF!!!

I have no idea at this point and chasing the wires is very difficult-they disappear into the chassis.

Any thoughts?
 
if one light works, so should the other.

the circuit is ran parallel

you have a broken wire.

do you have those worthless tweeker clips on any of the wire you may have used for a trailer plug.

there is no fuse for each light. there is a fuse for the complete circuit.

i dont even think there is a relay.

the wire from one tail light to the other is broken or corroded.
 
No trailer harness. Completely stock.

Parallel wiring? I see two sets of the same wire (park light) coming from the harness (cabin). Then there is a cross wire bunch (4-5 wires) between the two rear lights.

It is very odd.

IF it was a parallel circuit, I would think I would see one set (one per light bulb) coming into the rear and then split but that is not the case.

Pin, do you have an actual wiring diagram for the rear? I cant find my Volume II of my FSM.

I would like to understand why in the hell there are so many wires IF it is run in parallel.

Thanks all.
 
OK. Took it to the dealer because I was completely fed up with it.

The b+ for that side apparently was nicked/rubbed above the fuel tank. So, they ran a by pass for that part of the light circuit.

Just as a follow up, the left and right side tail lights are 2 completely different circuits i.e. dedicated b+'s and grounds for each side.

Problem solved.
 
Jukelemon said:
OK. Took it to the dealer because I was completely fed up with it.

The b+ for that side apparently was nicked/rubbed above the fuel tank. So, they ran a by pass for that part of the light circuit.

Just as a follow up, the left and right side tail lights are 2 completely different circuits i.e. dedicated b+'s and grounds for each side.

Problem solved.
Click to expand...
Hey Man, I know this is a super old post, but I'm having the same issue on my '00 Tacoma, all stock wiring. I put a new tail light assembly on, checked fuses and swapped in a new bulb and still that driver's brake light is not working. All other lights on the whole truck including hazards work correctly. I'm kind of a dummy when it comes to electrical issues...can you explain what the b+ side is/means? I'm trying to solve this without having the dealership bend me over...
 
You must log in or register to reply here.

Share this page

Back
Top Bottom