1990 GMC V1500 Jimmy Flashing Brake Lights

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

GMC Gremlin - 17 Feb 2005 14:31 GMT

1990 GMC V1500 Jimmy
350CUI TBI
TH700R4
NP241
10B front/rear
3.73 front/rear
ABS rear - in working condition (maybe, was until the following
incident but haven't tested it since so it may still be working who
knows....)

After an extremely forceful application of the brakes at about 55MPH
that locked up the fronts and I'm sure started to utilize the ABS in
the rears, my brake light has been on steady for about 1 week. Just
after the incident I stopped and tried removing the 1 wire that goes to
the proportioning valve, and this does NOT turn off the light so I
don't/didn't think it was a pressure thing. I thought my parking brake
switch was out of alignment (lifting up on lever doesn't fix it) and
just kept on driving it. I haven't checked the p-brake switch though.

This morning it started tweekin out, thought maybe it would go out
(flashing on and off randomly)
Then it got rythmic;
7 short
1 long
7 short
1 long
etc.

Turn off the truck, and put the key in "run" and it does the same
thing. NOTHING has been jumpered AFAIK, so I don't have the truck in
diagnostic mode - unles it shorted somewhere in the loom.

Everything seems fine in operation??
I'm in work right now so I can't consult my repair manuals.

GMC Gremlin

Reply to this Message

GMC Gremlin - 17 Feb 2005 18:50 GMT

P.S.
I mean the warning

BRAKE
( P ) ( ! )

light, not the brake lights you would see outside of the car.
JJJJJJJJJJJJJJJJJJJJJJJEST to make sure. The subject I chose sucks!

GMC Gremlin

Reply to this Message

shiden_kai - 18 Feb 2005 02:21 GMT

> This morning it started tweekin out, thought maybe it would go out
> (flashing on and off randomly)
[quoted text clipped - 8 lines]
> thing. NOTHING has been jumpered AFAIK, so I don't have the truck in
> diagnostic mode - unles it shorted somewhere in the loom.

Unplug the connectors to the RWAL module that sits right
beside/under the master cylinder. Plug them back in after
about 30 seconds...see if the light goes out. These were famous
for setting false codes. If the light comes right back on, probably
pretty sure that you have an actual problem.

Ian

Reply to this Message

GMC Gremlin - 18 Feb 2005 02:27 GMT

So the computer by the MC, that has a bunch of wires, right?
NOT the proportioning valve with 1 wire.

GMC Gremlin

> > This morning it started tweekin out, thought maybe it would go out
> > (flashing on and off randomly)
[quoted text clipped - 16 lines]
>
> Ian

Reply to this Message

shiden_kai - 19 Feb 2005 01:16 GMT

> So the computer by the MC, that has a bunch of wires, right?
> NOT the proportioning valve with 1 wire.

Yes, there should be two connectors at the module.

Ian

Reply to this Message

GMC Gremlin - 23 Feb 2005 23:37 GMT

How do they come off?
They both are blue and white. It looks like the white pin is a "safety" that
needs to be removed before the connector can come off? Just don't want to
break it since the white bit wasn't coming off too easily.

GMC Gremlin

> > So the computer by the MC, that has a bunch of wires, right?
> > NOT the proportioning valve with 1 wire.
>
> Yes, there should be two connectors at the module.
>
> Ian

Reply to this Message