'88 5ktqa brake warning light mystery

[Bernie Benz]

Ben,

I sold my 5K Bentley so can't help in detail, but it must be very similar to
the 200-20V.  Do you have the 5K Bentley?

The "(O)" symbol is the pad wear symbol, is it not?  A good pad wear system
provides ground to the board computer display.  If grounding the lead from
the driver's side pad wear connector to the display (bn/bk?) does not
eliminate the light you most probably have an broken wire, BTDT.  The pad
side of this connecter /wire should be at ground thru the two pads.  I
couldn't find the break so went upstream somewhere in the engine compartment
and permantly grounded the wire there.  IMO, you don't need pad sensors
anyway, inasmuch as the backing plates rubbing on the unworn rotor surface
annular rings will give ample warning without damaging the rotor surface.

Bernie
 
> From: "Ben Swann" <benswann at comcast.net>
> Organization: Swann
> Reply-To: Ben Swann <benswann at comcast.net>
> Date: Fri, 23 Jul 2004 14:17:22 -0400
> To: <quattro at audifans.com>, <200q20v at audifans.com>
> Cc: Ben Swann <benswann at comcast.net>
> Subject: '88 5ktqa brake warning light mystery
> 
> Ever since I have put this '88 5ktq avant back together again and pretty much
> eliminated any quirks, a problem still eludes me.  Brake pads are relatively
> new all-around, all reserviors full and power steering pump has been changed
> to known good working one, fresh pentosin hydr. fluid, etc.  Yet I get this
> brake warning symbol when the ignition is turned on, regardless of whether
> engine is running or not.  This is the Brake or ((!)) symbol which stays on
> for the duration while ignition is on.  Occasionally I get a red triangle
> warning for brake pads worn when I step on the pedal hard/more forceful
> braking.  I checked the lead to the padwear indicator and both sides in front
> have continuity, and being sceptical, I bypassed them with a jumper wire, but
> it doesn't  help.
> 
> ABS seems to be working fine, and braking and steering seems to be working
> fine.
> 
> Anyone have this happen before?  What could be triggering this?  Perhaps there
> is a sensor somewhere that I have overlooked - so far I have checked: 1) pad
> wear indicator leads front right and left, 2) power steering /hydr. fluid
> reservior, 3) Brake fluid reservior 4) pressure sensor located at back of
> MC/brake booster  cyl.  There is another set of leads near brake res. tied off
> that are not connected to anything, but they were that way and I think I have
> seen them tied off on other cars.
> 
> Ben
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