Think I may have problem solved very simple. I believe it is the wire
attached to the top of the proportional valve removed it cleaned and
replaced straightened the wire and reattached and now light doesn't come on
but if you bend the wire at top of clip light comes back on again, bad
connection from clip to wire?Does this sound plausable? (Where can I get
one of these rubber covered snap on clips.) Thanks for help to all who
answered. Have filed help answers for future referance.
Marlene Meineken
77 Palm Beach
Kendrick, Idaho
- ----- Original Message -----
From:
To:
Sent: Friday, August 27, 1999 6:02 AM
Subject: Re: GMC: Brake Light
> In a message dated 8/26/99 11:27:32 PM Eastern Daylight Time,
>
> This is just a guess because I don't have the wiring diagrams in front of
me,
> but there might be a switch on the parking brake lever that turns on the
dash
> light when you set the brake. Next time the light comes on check to make
sure
> the parking brake lever is completely down. (Someone please correct me if
our
> coaches are not equipped with a parking brake warning light switch.)
>
> Richard >>
> Richard the parking brake light is in the tell-tale light panel not in the
> round gauge unit that Marlene mentioned. The Tell tale has, starting from
> the left, Cruise, Door open, low air (not used), park brake on, low fuel,
set
> power level to travel. This might vary in early years but is accurate for
75
> to 78.
>
> The brake light that comes on in the lower right of the round Gauge
Cluster
> (fuel gauge at top) is not parking brake related but it is truly a brake
> warning light and should not be ignored. It is triggered by the
proportional
> valve located on the left frame behind and above the driver's side front
> wheel. The proportional valve has brake lines going into it from the
master
> cylinder and out to the front and rear calipers and wheel cylinders. Ther
e
> is an internal sliding valve that should normally be centered. If the
> pressure is lower in the front brake circuit the valve slide forward and
the
> switch grounds the wire coming into the top of it. The same thing happens
> when the back brake circuit has lower pressure. Marlene -- try pulling
the
> wire clip off the top of the proportional valve (turn on your key) and
with
> it disconnected the brake light should go out. When you ground it to the
> frame or other ground it should light. It may be that you've got a short
in
> the wire somewhere or you might actually have a brake problem. A sticking
> wheel cylinder could cause this. A faulty proportional valve could also
be
> the problem. Internal leak in the master cylinder or just air in the
system
> somewhere. If you have never replaced the front hoses you should try that
> first. They have a history of collapsing internally. This could cause a
> higher pressure in the front brake circuit and trigger the light. Bleed
the
> master cylinder and then all the wheel lines.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
>
