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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
Satisfied Customers: 4813
Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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My tail lights/marker light, license plate lights and fog

Customer Question

My tail lights/marker light, license plate lights and fog lights are not working. I have checked ALL fuses under the hood and under the dash.
Submitted: 1 year ago.
Category: Toyota
Expert:  Toyota Service replied 1 year ago.

Hello. Welcome to Just Answer. Please allow me to assist you. In order to determine the issue here we need a few easy to do voltages tests. Do you have the means to check voltage (DC testlight or DC voltmeter?)

Customer: replied 1 year ago.
Expert:  Toyota Service replied 1 year ago.

Please turn on the headlamps switch to illuminate the taillamps. Remove the TAIL fuse and test for power on each side of the TAIL fuse socket. Advise if one side fo the fuse socket has power.

Customer: replied 1 year ago.
The tow/tail fuse under the hood has power. (There isn't a tail fuse there). The tail fuse under the dash also has power.
Expert:  Toyota Service replied 1 year ago.

Do you have power at the Green wire at the taillamp sockets? If you do, you have a broken main ground wire under the bed of the truck.

Customer: replied 1 year ago.
There is no power from the green wire while the headlights are switched on. The outlet is not grounded either.
Customer: replied 1 year ago.
Any chance it could be the dimmer switch on the steering column?
Expert:  Toyota Service replied 1 year ago.

The Headlamps switch activates the TAIL relay. When it energizes, it powers the TAIL fuse. COnnector "A39", a 12 pin connector under the dash on the left side near the fuse panel supplies power to the rar tail harness. A green wire comes from the TAIL fuse and it outputs this power via the Purple wire. I would verify you have power in the green wire (into the connector) and power in the purple wire (out of the connector). If your rear outlets are not grounded, you need to locate and verify that the main rear wire harness ground junction (at the rear of the frame under the bed) is not corroded or has a broken wire.

Customer: replied 1 year ago.
I have power out of the green wire in the tail fuse and power out of the purple wire. I have no power from the green wire in the tail light socket even when it is properly grounded. The ground wire from the taillight socket does not appear to be grounded either. The lack of ground is confusing to me as the light comes on when I press on the brake.
Customer: replied 1 year ago.
I'll check for a broken ground wire tomorrow. I've got to go to sleep to get up for work tomorrow. Thanks.
Expert:  Toyota Service replied 1 year ago.

The brake lamp and the tail lamp use the exact same ground. This sounds like you have a break in the wire between the output connector (purple) where it splices into the rear harness (green). This may be had to find. You may need to strip the entir rear harness to find the issue. Personally, there is no benefit in wasting the hours it would take to cut apart the harness and fixing the issue in a bad wire. If this truck was in my shop I would be splicing into the powered purple wire, and running this wire along the existing wire under the bed to the rear lamps, the splicing into the green wire that powers the tail and license lamps.

Expert:  Toyota Service replied 1 year ago.

Ok. Goodnight.