Re: '91 S15 Jimmy parking brake warning light is on constant

>I have a '91 S15 Jimmy. The parking brake warning light is on constant. I
>have checked the fluid level and it is fine. I also tried tapping the
>parking brake while releasing it. Tried this several times.
>
> I noticed that when I depress the parking brake, the light gets a little
> brighter.
>
> What else can cause this light to stay on constant?

This could indicate a failure in the hydraulic system. Check fluid level and
check for leaks.

Steve

> Thanks like I said in my message above, the fluid level is fine. If I
> had a leak wouldn't it be down?

Not necessarily...

>> This could indicate a failure in the hydraulic system. Check fluid level
>> and check for leaks.

I just read that it could also mean there is a problem with the ABS light
circuit. Does the ABS light come on when you turn the key on? If so that's
not the problem. So it also comes on when the p-brake switch is grounded
out. Unplug the switch and see if the light goes out (the switch is above
the peddle). The other way the light can set is by the "combination valve
differential pressure switch".

Steve

If the '91 has the same setup as my '89 w/rear ABS it would set mystery
codes when ever damp, wet or snowy winter weather came in. No ABS light on
the '89 , the brake light was used.
Codes would say bad solenoid, reset and would be fine for awhile. Never a
prob. in summer only winter.
My brother's got the truck now w/over 170k miles and the last 2 yr. it
hasn't set the ABS code but he hasn't been going up to the north country in
the mega salt either.
--
John
"anything you say can & will be misquoted & used against you"
'01 FLHR ''Red"
'04 MXZ 600ho
'99 XC700
BRC mem

> If your saying the ABS light is NOT coming on when you turn the key. (
> it should come on when you turn the key to start the engine, then go out
> after a second or two once the engine starts) Then you have a problem in
> the ABS system, check for a blown fuse.

Exactly, if the ABS light does NOT come on when you turn the key forward,
before startup, then the brake light comes on to tell you there is a problem
with the ABS light circuit.

Steve

> Just checked it again. The ABS light is definitely NOT coming on. I did
> see it flicker once in the half dozen times that I tried starting the
> car, so I am pretty sure the bulb is OK.

Hrm, do this. With ignition off, short terminals "A" and "H" of the ALDL
connector (should be under the steering wheel in plain sight). It looks like
terminal "A" is the top right hand corner one, and terminal "H" is the
second from the left on the bottom row.
(http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm see "12 pin US
style")
Using a paper clip is popular. Turn ignition to ON position, do not start
the vehicle. Watch ABS light, count flashes, report back.

Steve

> What is the circuit on the link that you sent? Can I use a laptop to
> dignos the system?

Yes, the circuit is the device you need to build to connect a laptop to a GM
ALDL 8192 baud diagnostic port. Your vehicle is an ALDL 160 baud I believe,
and requires a different circuit. But this wouldn't help you in your
situation. Just getting the codes will help enough.

Steve