Ignition, by switching on your cars electrical system
It is possible that the problem you are experiencing with your 1999 Volkswagen Passat is caused by a fault in the vehicle's headlight switch. The headlight switch controls the operation of the tail lights, as well as the head lights, and a malfunction in the switch can cause the tail lights to only function when the high beams are on. It is also possible that the issue could be caused by a problem with the wiring in the vehicle, such as a loose connection or a short circuit. I recommend having a mechanic diagnose and repair the problem, as it could be a safety issue if your tail lights are not functioning properly. The mechanic will be able to determine the cause of the problem and repair it for you.
I had a similar problem with my S70 and discovered the headlight switch was defective. The switch had actually begun to separate causing the contacts for the tail lights not to make contact. Try having someone observe the tail lights while you push on the headlight switch. If the tail lights begin to work, replace the headlight switch.
You may have to replace the headlight switch since your tail lights are tied into the same switch.
Dash lights and tail lights are on the same fuse.
Those tail lights could be the brake lights you are seeing and that would be a faulty brake light switch or the brake light switch is out of adjustment.
They are two separate circuits, each has their own fuse. The brake lights not working could be caused by a few things such as a blown fuse, blown bulbs, bad brake light switch, misadjusted brake light switch and depending on what vehicle you have, a bad signal light switch.
Tail markers and stop lights must be red. Turn signals can be red or amber.
Either the switch that turns the backup lights on is out of adjustment, or has failed in the on position.
First, check the tail lights. Turn on the headlights and see if the tail lights come on at the same time. If the tail lights come on but the dash lights don't, it's probably either the switch or the bulbs. If NEITHER come on, it could be the switch, the fuse and of course, still the bulbs.
For Temporary Fix, By A Rocker Switch From Auto Parts Store. Pull Your Head Light Switch Out Of The Dash Wire In The Rocker Switch. Will Have To Find Wiring Diagram Or Chiltons Book For Wiring Schematic For That Year Of Vehicle. Only Temp Fix, Should Replace With Stock Switch For That Vehicle.
Brakelite switch is probably stuck
There is no electricity going to the lights of an automobile if the light switch inside the car is off. The main switch cuts off all current to the lights, both front and rear. There will be current to the tail lights if the brake is applied.