2005 focus. Tail light on left side works infrequently. The brake, flasher, and signal works all the time but not the regular tail light. This usually happens in hot humid and sometimes rainy weather. Once the car cools down after a few hours the tail light will work. I changed both bulbs 3 days ago and they both worked for 2 days. The left one did not work again until I was at work for a few hours. I also don't get the quick blink on the dash that you usually get when you have a tail light out.

USA car answer, you never said country

the license plate wire, to LED in turn new is here
OG/BLK

BK ON BOTTOM IS GROUND./

The tail light is usually a bulb with lower wattage, so it won't glow as brightly as the brake and turn lights.. There should be one or two other bulbs in either of the two tail assy's. The turn signal can use the same bulb as the brake light. If so, it's up to the flasher assy to direct the lights to both come on, and/or for one to flash if the brake and turn signal is on, e.g.. There could also be a backup light.

So if the brake and turn lights don't operate, look to the fuses, and flasher assy. for possible replacement.

You should have the computer scanned for trouble codes for the warning light.
As for the tail light, I would check the socket with a test light or meter to see if the socket is getting power for that circuit. The brake-turn signal circuit of the bulb is different from the tail light circuit.

When you are talking about "indicators" we could assuming that your are refer about signal lights. This work with "flashers" devices.

For 1996 Audi A4 2.8L SFI 6cyl the Flasher is located in front seating area, driver side, under dash, behind dash lower panel, mounted above driver side of steering column.

About generic fuses, open the driver side door. Remove panel on left side of dash. Fuse box is behind panel:

Fuse # / Description / Amps
1 / Heated washer jets / 5
2 / Turn signals flasher unit / 10
3 / Headlight washer, illumination of glove compartment, engine compartment, climate control, automatic transmission, instrument cluster / 5
4 / License plate light / 5
5 / Instrument cluster, seat heating, test connection for cruise control, bulb monitor for auto-check control, Automatic transmission display, switch lighting, mirror switches and actuators, airbag warning light, outside temperature indicator, Climate control / 10
6 / Central locking system / 5
7 / Anti-lock brake system / 10
8 / Vacant
9 / Mirror heating / 10
10 / Vacant
11 / Cruise control (automatic transmission) / 5
12 / On board diagnostic system / 10
13 / Brake lights / 10
14 / Interior lights, reading lights, anti-theft alarm system, vanity mirror / 10
15 / Instrument cluster, power windows, climate control, automatic transmission / 10
16 / Anti-lock brake system, Anti-Slip-Regulation / 5
17 / Heated door locks / 10
18 / High beam right / 10
19 / High beam left / 10
20 / Low beam right / 15
21 / Low beam left / 15
22 / Tail and side marker right / 5
23 / Tail and side marker left / 5
24 / Wiper and washer system / 25
25 / Blower for heating, climate control / 30
26 / Rear window defogger, mirror heating / 30
27 / Rear window wiper / 15
28 / Fuel pump / 15
29 / Engine timing / 20
30 / Sun roof / 20
31 / Tail lights, cruise control, automatic transmission / 15
32 / Engine timing / 20
33 / Cigarette lighter / 15
34 / Engine timing / 15
35 / Trailer receptacle / 30
36 / Fog lights / 15
37 / Radio / 20
38 / Luggage compartment light, central locking system / 15
39 / Emergency flasher / 15
40 / Horn / 25
41 / Anti-lock brake system / 25
42 / Vacant
43 / Vacant
44 / Seat heating / 30

Hope this helps (remember to rate and comme this free answeer).

I'm inclined to believe it is the turn signal switch. When you select left or right, the brake light is removed from that side, and the flasher is connected to the bulb instead, making the brake light on that side flash as the indication that you plan to turn. You have lost everything, but the simple answers check out.

If you have lost signals, brake lights and tail lights, then it is more likely that the ground supplied to the bulbs is not working, since the tail lights share noting in common with the brakes lights and turn signals but ground.

If the tail lights work, the fact that the brake lights and rear turn signals share that switch starts to look meaningful — even more so if the front turn signals also don't work. But the front signals and the rear signals use different circuitry in the switch, so it would be something more mechanical in the switch than electrical in that case.

the upper brake light works differently than the outer lights. check your brake light switch by the brake pedal.It will have a plunger switch on it. The center brake lamp works off a power convertor instead off the brake light switch. The switch has a separate wire for that which is still working

the source of this problem is the turn signal switch
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Source: rockauto.com

i see this problem alot and there are many different reasons each time. sometimes its the actual tail light capsule and sometimes its the running light wiring to the bulb

Hi, you have a bad bulb,....

I just chaged my left tail light bulb, it's working.