Brake Light Switches: 1978 911 sc

[BierSlinger]

I've done my searching some pre, some post, brake light switch job and I've come up with a few questions regarding the issue.

Infamously it seems, the emergency brake light turned on a few months ago. Did the research and tests and came up with a faulty switch. I replaced them both with the appropriate switch but failed to think about torque specs. I installed properly, brake pedal depressed little fluid in the switch and off I went. Worked well for a couple good and long spirited drives but the light came back on. I've been pondering this problem lately and came up with this theory: since I failed to torque them down not only to the correct spec but also unevenly the system is sensing different pressures as if one one switch is actually faulty and setting off the light. First off, am I correct? And second, if I am can I simply remove the switches and reinstall with the correct torque on each switch and except that as a fix or should I replace the switches again, start anew? And I guess third, if I'm completely wrong what's the next step?


Also I'd like to mention, Porsche built this system in 78 to work without the mechanical switch so I'd like to keep it that way.

[emac]

Bier-- disconnect neg cable from battery for a minute. This will reset the light. I never torqued the switches, don't believe that has anything to do with your issue. With car running does the brake pedal slowly go down. If so it could be the M/C which could be leaking through itself. This will trigger the light.
Ernie 81sc

[timmy2]

A burnt out brake lamp will turn on the light as well, disconnect battery neg to reset.

[jhmol]

Bier, Any resolution to your e-light problem? I've got an 82 with a similar (identical?) problem. The e-light is on. I've done the battery disconnect thing for 6 months now. The light goes out and comes back on after light use of the brakes. Replaced both brake switches on the mater cylinder and the light came on again (still). The brakes are good. Solid and no swerving. Someone must know what is going on. I understand that the switches sense a difference in pressure. Where is the decision made to turn on the e-light? Is there another switch/module somewhere?