2005 e4 parking brake


I have a 2005 e4 that will drive forward with the parking brake engaged with no error codes displayed, no parking brake light illuminated on the display screen, and no warning beeps. I have first replaced the parking brake micro switch located at the parking brake but no change so the original switch was obviously not bad. I have verified under the car that the 2 wires running from the parking brake to the T3 controller are not cut.

Could replacing one of these switches below fix this problem? Do the switches below fit the 2005?
0306-00107 Brake Lamp Switch
0306-00108 Brake Failure Switch


Check the brake lamp switch under the dash, not the over travel switch next to it. Also check the brake indicator lamp. I do not believe the the over travel switch is the issue.


Thanks Daniel !!!

Note that these brake light switches can be successfully taken apart and cleaned/lubricated. I just did this on my 2002 GEM with good results. Just pry the 4 metal tabs apart and carefully remove the switch’s bottom plate off, being careful not to lose the springs or sliding parts. A light sanding with Emory-cloth and lubrication with dielectric grease will give the switch many more miles of use. Simply reassemble and bend the hold-down tabs back into place.

Thanks Bob! Do you think this bad brake light switch is what’s allowing my car to drive with the parking brake engaged?


I just learned that the 0306-00107 Brake Lamp Switch is only found in 1998-2004 models. If this is correct then my 2005 does not have this switch. This is really frustrating!


[QUOTE=gem4me;14402]Thanks Bob! Do you think this bad brake light switch is what’s allowing my car to drive with the parking brake engaged?

Brad[/QUOTE]Nope. The parking brake disable circuitry is part of the electronics surrounding the main contactor (I think). It senses the parking brake micro-switch and should cause a -04 on pre-2008 models when the ignition switch is turned on. I’ll have to look at mine but I thought there were 3 wires, not 2 on the switch…

The brake lamp switch, the upper of two on the brake support bracket, is a simple single-pole, singe-throw switch which directly interrupts 12 volts to the brake lamps. It should be adjusted to turn on the brake lamps when the pedal is slightly depressed but not so tight that bumps in the road cause them to flash on and off when you hit them.

The lower switch is a brake pedal over-travel switch which illuminates an indicator on the dash to warn you of brake failure. If one of the two brake hydraulic paths leaks, the pedal will travel far enough to trip this second switch and light the red warning lamp on the dash cluster.

I suspect your problem is wiring or the switch on the parking brake handle. If the wires between the switch and control logic are cut or pinched where they pass under the cabin floor it could cause the GEM to be able to move with the parking brake still engaged.


Thanks so much for explaining the function of the brake light and travel switches. Obviously replacing either of those would not correct my problem. Daniel said the same thing about the parking brake micro switch (located at the hand brake) usually having 3 wires but mine only has 2. I wish I could find out for certain if I am missing the 3rd wire and if so what color each of these 3 wires should be. I don’t think the switch is bad because I get the solid beep when I turn the key off until I engage the parking brake.


There are 3 wires on my 2002 GEM eL for the parking brake switch.

The top one on the top of the switch is solid green
The middle one on the upper of the two end contacts is white
The bottom one on the lower of the two end contacts is yellow with a green stripe