Third brake light stays on

It says the tachometer wire is Yellow/Green, you do not have that listed. You will find it in the list below, it is highlighted..

WIRING INFORMATION 2001 Subaru Legacy

WIREWIRE COLOR LOCATION

12V CONSTANT WIRE WHITE Ignition Harness

12V IGNITION WIRE GREEN Ignition Harness

12V ACCESSORY WIRE YELLOW Ignition Harness

STARTER WIRE WHITE/BLACK Ignition Harness

POWER DOOR LOCK (-) WHITE Harness In Driver's Kick Panel

POWER DOOR UNLOCK (-) GREEN/RED Harness In Driver's Kick Panel

PARKING LIGHTS (+) ORANGE At Light Switch

DOOR TRIGGER (-) PINK/BLACK In White Connector Behind Fuse Box

TRUNK TRIGGER (-) YELLOW/BLUE In White Connector Behind Fuse Box

TRUNK RELEASE (5-wire) LT.GREEN/YELLOW At Motor In Tail Gate

FACTORY ALARM ARM (-) Factory remote only

FACTORY ALARM DISARM (-) Factory remote only

TACHOMETER YELLOW/GREEN At Ignition Coil

BRAKE WIRE (+) WHITE/BLACK At Brake Pedal Switch

HORN TRIGGER (-) RED/GREEN Harness At Steering Column

LEFT FRONT WINDOW UP BLUE/RED At Driver Window Motor Inside Door

LEFT FRONT WINDOW DOWN BLUE At Driver Window Motor Inside Door

RIGHT FRONT WINDOW UP BLUE/RED Harness In Driver's Kick From Driver Door

RIGHT FRONT WINDOW DOWN BLUE Harness In Driver's Kick From Driver Door

LEFT REAR WINDOW UP BLUE/RED Harness In Driver's Kick From Driver Door

LEFT REAR WINDOW DOWN BLUE Harness In Driver's Kick From Driver Door

RIGHT REAR WINDOW UP BLUE/RED Harness In Driver's Kick From Driver Door
RIGHT REAR WINDOW DOWN BLUE Harness In Driver's Kick From Driver Door

The red lights represent the actual rear lights of the car's brake and signal indicator lights, also would alert you when bulbs were not functioning properly.

1) Locate and remove sensor.
The sensor is located under the drivers tail light. Unclip it from the body and then unplug it.

2) Bypass the tail light circuit.
Connect the tail light signal wire (Green) to the tail light wire (Green w/ Red Stripe). I recommend using wire tap in squeeze connectors that way you dont have to cut any wires.

3) Bypass the brake light circuit.
Connect the brakelight signal wire (Green w/ White Stripe) to the brake light wire (Red w/ Blue stripe) and the the 3rd brake light wire (Red w/ White Stripe). Again all three of these wires are to be connected together.

4) Throw away your broken Tail Lamp Failure Sensor
Do not plug your sensor back in. Doing so will cause the annoying orange lamp failure warning light on your dash to stay on. Leave it unplugged ant the light will stay off.

5) Test your work
Turn on your lights and make sure your tail lights work properly. Have a friend step on the brake pedal, and make sure your brake lights work properly as well. Dont forget to check the Third brake light.

The third brake light is the brake light in the center of the vehicle either around the lower part of the rear window or above the rear window. They didn't start to become common until the late 80’s - early 90's. It is also known as the high mount brake light or the cyclops break light? If that's not what you where looking for let me know and I'll be happy to help you further. Thank you for using fixya.com

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Are the brake lights on at the rear of the truck? You have a wiring problem.

| ITEM | WIRE COLOR |POL| WIRE LOCATION |
| 12V|red/grn & red/org |+ |ignition harness |
| STARTER|gry/blk or lt. blue |+ |ignition harness |
| IGNITION|green/black |+ |ignition harness |
| SECOND IGNITION|pink/white |+ |ignition harness |
| THIRD IGNITION|red/wht (key sense)|+ |ignition harness |
| ACCESSORY|yellow |+ |ignition harness |
| SECOND ACCESSORY|pink/yellow |+ |ignition harness |
| POWER LOCK|black/blue |- |DDM *1 |
| POWER UNLOCK|black/white *2 |- |DDM *1 |
| LOCK MOTOR|yellow/black | |DDM *1 |
| UNLOCK MOTOR|white/purple | |DDM *1 |
| DISARM DEFEAT|white/green | |pass. kick, harness to rear |
| PARKING LIGHTS +|use neg. wire only | | |
| PARKING LIGHTS -|white/green *3 | |headlight switch |
| HEADLIGHTS|white/green *3 |*3 |headlight switch |
| DOOR TRIGGER|black/white *4 |- |underdash light |
| DOME SUPERVISION|comes on w/unlock | | |
| TRUNK/HATCH PIN|white/black |- |REM *5 |
|TRNK/HTCH RELEASE|black/blue |- |release switch or REM *5 |
| FCTRY ALARM ARM|arms w/ lock | | |
|FCTRY ALRM DISARM|disarms w/ unlock | | |
| TACHOMETER|brown or brn/stripe | |main harness pass. firewall |
| SPEED SENSE| | | |
| BRAKE WIRE|org/yel or org/blu |+ |brake pedal switch |
| HORN TRIGGER|gray/orange |- |FEM *5 |
| WIPERS|red/blk(L),red/grn(H|+ |wiper motor |
| LF WINDOW UP/DN|white - yellow |A |DDM *1 |
| RF WINDOW UP/DN|wht/pur - yel/pur |A |FEM *5 |
| LR WINDOW UP/DN|blu/red - pur/blu |A |REM *5 |
| RR WINDOW UP/DN|blu/orn - pur/wht |A |REM *5 |
| RADIO 12V|orange/black |+ |radio |
| RADIO GROUND|black |- |radio |
| RADIO SWITCH|yellow/green |+ |radio |
Notes:
NOTE: This vehicle is equipped with a passive immobilizer that needs to be bypassed for remote start operation only. Use DEI part number 555U to bypass. *1 The DDM (drivers door module) is located in the center of the drivers door. *2 Requires a double pulse to unlock. *3 Parking lights require a negative trigger with a 1800 ohm resistor in-line to the white/green wire. Using a negative trigger with a 780 ohm resistor in-line to the same white/green wire will turn on the headlights as well as the parking lights. *4 This wire may cause the aftermarket alarm to false when the vehicles electrical system shuts down. Use a relay to isolate it. *5 The FEM (Front Electronic Module) is located in the drivers kick panel. The REM (Rear Electronic Module) is located in the trunk, just above the battery. hope that helps

It may be a turn hazard module under dash.that is the culprit! The power to the third brake light does not go through the module, but the rear brake lamps power is controlled through this module. I am looking at a drawing of one and it looks like it has two connectors with about five wires in one and six in the other. It has some cooling fins on it also.