Main Menu

Slow Brake Lights


Vehicle Information: Model: Carrera; Year: 1984; Body Type: Convertible; Engine (type, size, modifications): 3.2L; Total Mileage: 90K;

Hi Chris,I see a few posts on slow brake lights and even see that Jim wrote you about adding a Arc Supressor to the Brake Switches on the mstr cyl. Not sure what Jim is selling but I agree with his findings that these switches are burning out because of the high current (5-8amps) that is wired through them. I simply added a 30amp SPDT relay to the switches so that the switches pick/activate the relay with less than .5amps and the relay activates the lights. I put 2 new switches in as well and now I have properly working brake lights.I'm including a picture of the bad switch I took out just to show you how bad the internals of the switch are. I'm a EE by education and can tell you this switch is damaged because of high current causing severe arcing. Also the stock switch configuration cuts the '+' side of the circuit which is also a bad idea, Electrical theory 101 teaches that arcing increases if a DC circuit is cut by a switch on the '+' side of the load. It's always best to have the switch cut the '-' (ground) side of a circuit.If you are intrested in the details of my relay install and schematic of how it was wired as well as pictures let me know.I really think the stock design for these brake lights can be improved and thus extend the life of the switches. It's not often I can say this about the 911 design but this can be improved.Thanks for your time.

You must log in to view answers associated with technical questions. Join PCA to participate in our community.
No votes yet