1994 GMC Sierra 1500 is eating batteries - Page 3

crabtruck · 07-26-2009, 08:54 PM

GMC has a good point about the add-ons. look for spliced wiring between fuse and pedal.

Also even tho you may not have the ABS, the harness may have a loose wire end for that
with bad insulation at end or corrosion at a plugend/pigtail.

Mostly a visual chase now, thank goodness it's not whole truck but narrowed to brake fuse.

May want to pull anything plugged in the convienence center (box by fuses)
not in a scientific manner, just pull all one by one
rather than figuring out who's who because it's 10x faster.

Brake relay is under hood on firewall near master, usually for third light. Good catch.
But should not go hot without pedal.

RollTidenIA · 08-04-2009, 12:21 PM

I have an update:

It's been busier than heck around here, but I took a few minutes the other day to check a few more things. I finally narrowed it down to a small black 'control' box mounted to the bottom of the master cylinder. If I unplug the top wiring harness on the back of that box, the test light nearly goes out completely. If I touch it back to the box, it lights right back up. I tried cleaning the connections on the harness and the box, but no joy.

Anybody know what that box is, and where to get a replacement? I searched on a few auto parts websites for "brake control", etc., but nothing comes up like what I'm looking for.

I sold the truck to a buddy last Saturday

so it's his problem now, but I'd like to help him find a solution for it.

badtothebowtie · 08-04-2009, 01:45 PM

that little black box iv been told is some kind of roll control i have a spare is u will pay the shiping and a little for the part i no it works cause it is curently on my daily driver but im putting in a different master the has one on it

crabtruck · 08-04-2009, 03:57 PM

Any chance of a picture of that from either of you guys ?

94GMC15002WD · 08-04-2009, 07:41 PM

im the schmuck who bought the truck.

crab - ill try to get a picture tomorrow.

bowtie - if it turns out to be the right thing i'll probably buy it!

94GMC15002WD · 08-05-2009, 06:06 AM

oh FWIW the voltage oscillates about a volt when the blinker is on.

crabtruck · 08-05-2009, 05:42 PM

Welcome to the forum 94GMC15002WD

"schmuck" is a little harsh, besides some of us don't appreciate when you
make a quick grap for something we've worked long and hard on.

Quote:

Originally Posted by 94GMC15002WD

oh FWIW the voltage oscillates about a volt when the blinker is on.

Pretty much normal imo, adding/dropping the lamps "suddenly"

94GMC15002WD · 08-05-2009, 07:49 PM

here is a picture of the mystery black box, as it is installed right next to the master cylinder/reservoir. Tell me what you think it is. Thanks!

silverhairdeere · 08-05-2009, 08:47 PM

i'am going to say engine management system or computer , looks just like mine .

shd

94GMC15002WD · 08-06-2009, 04:56 AM

Silver - could you look and see if there is still a part number on yours?

08-04-2009, 12:21 PM	#22
RollTidenIA Full Member Join Date: Jul 2009 Location: Iowa Posts: 18	I have an update: It's been busier than heck around here, but I took a few minutes the other day to check a few more things. I finally narrowed it down to a small black 'control' box mounted to the bottom of the master cylinder. If I unplug the top wiring harness on the back of that box, the test light nearly goes out completely. If I touch it back to the box, it lights right back up. I tried cleaning the connections on the harness and the box, but no joy. Anybody know what that box is, and where to get a replacement? I searched on a few auto parts websites for "brake control", etc., but nothing comes up like what I'm looking for. I sold the truck to a buddy last Saturday so it's his problem now, but I'd like to help him find a solution for it. __________________ 94 GMC Sierra 1500 - 4.3L - 239,000 miles and counting... SOLD 90 Jeep Grand Wagoneer - 360 - stock 'grocery getter'... 03 Jeep TJ - 4" lift - front Lockright - 33" BFG KM2's - weekend warrior...

08-04-2009, 01:45 PM	#23
badtothebowtie Senior Member Join Date: Jun 2009 Location: waterloo IL Posts: 158	that little black box iv been told is some kind of roll control i have a spare is u will pay the shiping and a little for the part i no it works cause it is curently on my daily driver but im putting in a different master the has one on it __________________ IF U GO OUT U HAVE TO DRESS UP WHY NOT WARE A BOWTIE

08-05-2009, 07:49 PM	#28
94GMC15002WD Junior Member Join Date: Aug 2009 Posts: 9	here is a picture of the mystery black box, as it is installed right next to the master cylinder/reservoir. Tell me what you think it is. Thanks! Attached Thumbnails

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07-26-2009, 08:54 PM	#21
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,091	GMC has a good point about the add-ons. look for spliced wiring between fuse and pedal. Also even tho you may not have the ABS, the harness may have a loose wire end for that with bad insulation at end or corrosion at a plugend/pigtail. Mostly a visual chase now, thank goodness it's not whole truck but narrowed to brake fuse. May want to pull anything plugged in the convienence center (box by fuses) not in a scientific manner, just pull all one by one rather than figuring out who's who because it's 10x faster. Brake relay is under hood on firewall near master, usually for third light. Good catch. But should not go hot without pedal.

08-04-2009, 03:57 PM	#24
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,091	Any chance of a picture of that from either of you guys ?

08-04-2009, 07:41 PM	#25
94GMC15002WD Junior Member Join Date: Aug 2009 Posts: 9	im the schmuck who bought the truck. crab - ill try to get a picture tomorrow. bowtie - if it turns out to be the right thing i'll probably buy it!

08-05-2009, 06:06 AM	#26
94GMC15002WD Junior Member Join Date: Aug 2009 Posts: 9	oh FWIW the voltage oscillates about a volt when the blinker is on.

08-05-2009, 08:47 PM	#29
silverhairdeere Senior Member Join Date: Feb 2008 Location: land between the lakes tn Posts: 1,622	i'am going to say engine management system or computer , looks just like mine . shd

08-06-2009, 04:56 AM	#30
94GMC15002WD Junior Member Join Date: Aug 2009 Posts: 9	Silver - could you look and see if there is still a part number on yours?