Brake Problem Solved

["Al Powell" <APOWELL@agcom.tamu.edu>]

Thanks to all those who helped me out last night when the brake 
lights were stuck on.  Since I bugged the list for help, I'll post 
"what I learned"...relative to my 1990 200.

a)  The brake pedal actuates *two* switches.  These can be accessed 
by removing the knee panel under the steering wheel.

b)  The bottom switch is for the cruise control.  It has both a 
vacuum port and an electrical contact.  The switch functions such 
that the electrical circuit is complete when the pedal is UP.  Also 
when the pedal is up, the vacuum port is sealed.  When one hits the 
brake, the cruise circuit is broken electronically, AND the vacuum 
port opens, releasing the vacuum required to hold the cruise control 
on.

c)  **NOTE if you are having cruise problems**.  The vacuum line 
running from this switch out thru the firewall to a T.  One side of 
the T goes directly to the cruise vacuum diaphragm; the other side 
goes behind the coolant reservoir and into the LF fender.  I believe 
there is a vacuum pump in there.  If your cruise does not work, these 
vacuum lines are a great place to look!!  (When I sucked on the 
vacuum line coming off the brake pedal switch, the engine sped up - 
but the vacuum bled away quickly.  I believe this is the source of my 
cruise control problems..)

d)  The switch for the brake lights is positioned a few inches 
*above* the cruise switch.  It's half-hidden behind the steering 
column, but not hard to access.  Pulling it out is likely to contact 
the steering column, causing sparks and blowing the 25A fuse (#3 in 
fuse box...of course, I only know this by rumor...)

e)  Adjustment for both switches is as follows, according to Bentley:

- Depress brake pedal
- Push switch fully down into its plastic collar mount 
- Pull UP on brake pedal manually to push both switches back up into 
their normal operating positions.

Note that there are NO retaining nuts on these switches - they are just a 
press-fit into the plastic retaining collars.  Unusual adjustment.

Thanks to all of those who very kindly responded.  I appreciate the 
help more than you know!  (About 30 minutes after I finished, working 
outside, it rained like crazy!)