500 sel (84) brake light on

This car sat for a year, fluid level is up and the parking brake working (engage and release) but this light is on all the time. What would you check/do to clear the on light.

Reply to
guzzi via CarKB.com
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Have owned a Chassis W126 ('81 380SEL USA model) The 500 is virtually identical. Consulting my old dealer W126 chassis manual(covers all those chassis including SE & SD models, as well), I found a few items that may help:

On the brake-fluid reservoir are two black-rubber buttons. Adjacent to each button is an electrical connector. Under normal circumstances, these buttons allow manual test of the low-fluid alarm. When either is pressed, the red park-brake indicator should light. Press them. Perhaps they are stuck. They should rebound to a convex-bubble shape. Perusing the electrical schematic shows that the disconnection of those elec. connectors adjacent to each button should disable this warning system, making the light go off, and proving that the switch is stuck closed.

The parking brake switch is directly above the pedal-beam. Follow upward from pedal, along the beam. Use a flashlight and prepare to remove the velour cover underneath the steering column (medium phillips-head screwdriver, and a little patience needed). Check the status of that switch with Pbrake released. Is it loose? If the metal beam is not pressing-in the switch, then the switch or parking brakes may need adjustment. The spec is no more than 4 notches out of the 12. This is to say, when pushing the park pedal, it should click no more than 3-4 times, before becoming solid to the feel. All Mercedes parking brakes are compIetely redundant to the driving brakes. They are cable-operated drums, independent of the four wheel disc-brakes. They only serve the rear wheels. Which is great--you have a *totally* separate stopping system available! Unfortunately, the park brake does not automaticaIly adjust, to my knowledge, as on other cars. It is a simple procedure, but very hard to describe. Your owner's manual may tell. I can e-mail the service manual pictures, if you need them. That parkbrake switch may be bad, or the connector to it. There would be no harm in removing the connector and jumping the socket with a piece of wire. This could eliminate or confirm trouble at the PB switch/connector. You didn't mention it, but it seems like the warning buzzer would sound constantly.

A remote possibility is that the wiring from the instrument cluster to the switches has chaffed, and contacted the grounded chassis metal. This will *not* blow a fuse, nor pose a fire hazard.

Reply to
M100

Is it the "BRAKE" light or is it the round circle with dashes?

Pull up the parking brake pedel to see if light goes out... if so, then see why your brake is not all the way up.

If it is the round circle... then you need brake pad changed.

Reply to
Tiger

M100 Thanks for all the great info, found the problem at the pedal switch (right were you said it would be) and fixed the problem. Again thanks for your help. Guzzi(79 convert w/sidecar)

Reply to
guzzi via CarKB.com

Tiger, Thanks for the help, found the problem at the parking brake plunger switch. Guzzi

Reply to
guzzi via CarKB.com

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