Re: "ABS off" warning light problem

[Andrew Duane USG/PE <duane@zk3.dec.com>]

Hairy green toads from Mars made Paul Hill 223-2154 say:

> I've been experiencing the "unsolicited ABS unlocked warning light
> illumination" syndrome on my '86 5KCSTQ.
> I recall some previous posts about this, but I'm a little confused about 
> what causes this lamp to light.
> Apart from the desired causes of manually disabling ABS (dash switch) and 
> locking the diffs, what caused this?
> I assume this is the fail safe mode when the control system defects an error
> of some sort.

This is a failure of one or more of the wheel sensors, or the wiring
that goes to them. I hit a 4" paving cliff last year, and torched
three of my wheels and tires. One of my ABS sensors went, too.
I would get the random ABS off you are seeing. While replacing that
sensor, I noticed that the wires to one of the other sensors had
chafed and was showing bare metal. I replaced it, too, and VOILA.

-- 

Andrew L. Duane (JOT-7)			duane@zk3.dec.com
Digital Equipment Corporation		(603)-881-1294
110 Spit Brook Road			http://www.zk3.dec.com/~duane
M/S ZKO3-3/U14
Nashua, NH    03062-2698

Only my cat shares my opinions, and she's too heavy to care.