Master Cylinder Sensor Fire ???

[CanadaRob]

I was sitting parked in my 96 Windstar 3.8. Ignition on but engine not running (doing some paperwork) when I looked up noticed thick white smoke pouring out of the dash and from under the hood. I shut off the ignition and popped the hood to see where the smoke was coming from. Underneath the front of the brake master cylinder there is a wire attached via a clip to a round cylinder beneath the master cylinder but attached. The thick white smoke was coming from this connection. I have disconnected this wire and have not noticed any difference in how the van operates and I have not had a repeat of the smoke.

Is this some sort of sensor ? What if I leave it unplugged ? How much $$$ to replace ? Could this have started a fire ?

Any comments would be greatly appriecated.
Thanks from Toronto.

[busboy4]

Hi Rob
I believe you are talking about the brake on/off switch (not necessarily the proper name). I know that it sends info to the cruise control as a secondary brake on indication, in addition to the switch on the brake pedal arm. I suppose it could have cracked/failed internally shorting out the switch. You should be able to unscrew and replace it . I changed mine once due to cruise control inop and paid around $22.

[CanadaRob]

Thanks for the info.

I will check it out and report back results.

[sahib]

Originally Posted by busboy4

Hi Rob
I believe you are talking about the brake on/off switch (not necessarily the proper name). I know that it sends info to the cruise control as a secondary brake on indication, in addition to the switch on the brake pedal arm.

In the Haynes manual they call it the "speed control pressure switch". I wasn't aware there was such I thing. Thanks for the heads up. Does anyone know of a place on the net/web that lists all these different sensors and their function. Like this one, Haynes identifies it but doesn't elaborate on what it's purpose is.