Changed my taillights now trying to figure out why I have a reverse twilight error message?
Hi Stephen, welcome to Planet-9 - the friendly Porsche forum!
In order to answer your questions - a bit of information is needed (better questions = better answers)..
- What year is your 987?
- What kind of lights are you installing
- Does "twilight" mean "taillight"?
As a WAG - lacking the above information.. probably:
- Your car is a 2008 or older (which used standard filament halogen bulbs)?
- You're installing LED lights?
If so - the bulb-out detection system thinks your taillights are burned out. This system sends a tiny pulse of low current voltage through the taillight bulb every so often. If the pulse doesn't complete it's path from the control module to ground - it assumes the bulb is out. The fix for this is to trick the system using a resistor. Most LED replacement lights have that resistor built in, but some of the less expensive ones don't and it has to be added externally. One will be required between each of these circuits: the running light circuit, the brake light circuit, and probably the turnsignal circuit.
It sounds as if all of those have a built-in resistor pack. It also sounds as if the backup lights don't.. assuming they used LEDs for the backup lights (and didn't use halogens and expected you to move them from your old lights.)
If your car was hooked to a Porsche specific diagnostics tool (see our Diagnostics forum for ideas on which one to get) the module probably will have stored the codes for each circuit and that would guide us in adding resistors.
You might contact the company that sold you the lights and ask if they have a resistor pack for the backup lights. If there is one built into it - chances are one of the resistors is bad.
If you haven't done it yet - please visit
New Member Introductions and fill us in about you, your car (pictures are almost mandatory), your automotive history/interests.. and again, welcome to Planet-9!
PS: Moving this to a 987 tech section of the forum. It is a better fit for that sort of forum. This (987 Chat) forum isn't so much about answering tech questions... hang on!
