ruhroh

I have a 2005 997.1 c2.

My hazard light switch was not working as of the beginning of this year. This is a weekend car so I figured I would replace it the next time I needed to take apart the dash.

I recently went on a week long trip and didn't think I would need to plug in my trickle charger, but when I came back, the car wouldn't start. While trying to unsuccessfully start the car, the hazard lights turned on and stayed on. I unplugged the battery and trickle charged it for 24 hours thinking that the hazards were a symptom of low battery power.

Turns out the battery is good enough and the car drives fine, except that the hazards are permanently stuck on. I have ordered a new hazard switch, but I'm anxious/worried this isn't as simple as it seems.

How does the hazard switch itself work? Is there a circuit within the switch itself that controls the hazards, or is it signaling to a computer in the car to turn the lights on and off? Is the switch supposed to have some sort of feedback indicating that it's in the on or off position? The one I took out of my car does not, i.e., each actuation feels identical to the next, which seems entirely different than all other cars I have driven. Obviously, I'm hoping that just the switch itself is defective.

Thanks for any help.

afishkind

I have the same problem - can't find any solution to this on any internet forums. Did you solve the problem?

Philster

Did you disconnnect the battery and then reconnect properly?

I'd be inclined to disconnect overnight if needed, then reconnect. Solved two gremlins I had with the radio and with Nav.

semicycler

Removing the hazard switch is not too difficult. You need to first pop out the center air vent. Be careful not to break off the vent tabs in the process.

Disconnect the switch and see what happens. There are four wires connected to the back of the hazard switch - GND, two LED's, and the switch itself. The switch wire is pin 3 on the hazard button, GND is on pin 5. Check continuity between pin 5 and pin 3 with a multimeter in both the pressed and unpressed positions. Plus if the lights stay on with the switch unplugged then it's probably not the switch.

The wires lead to the front end control unit, in the frunk on the passenger/right side behind the carpeting. Pin A28 is the switch input, pin A14 the indicator LED output. There's really not much to the input circuit unfortunately. I doubt you have a break or short in the wiring unless something was recently done in that area.

I haven't dug any deeper yet but suspect there is a relay somewhere downstream of the control unit on the output side. Do your turn signals work at all? What about all the other lights, including front and rear fogs?