97 2500 Diesel 4x4 has been getting Brake and ABS lights on the dash.

Started with the Brake light, and it would some times go off on its own or after a restart. Now I'm seeing the ABS light as well and it also goes off for awhile after a restart.

Brakes seem to be working fine, calipers, rotors and pads up front are a year or two old but probably only have 8K max on them. Rear cylinders and shoes have maybe 10 or 12K on them, maybe less. Master cylinder has plenty of fluid and no leaks anywhere that I can see, truck has about 105K on it.

Any ideas?

 

Have you checked your rear brake shoe adjustment?

 

When the rear wheel cylinders and shoes were replaced (about 10-12K ago) I set them for a moderate drag. They have not been checked since, can this cause my issue?

Searching google I see a lot of people mention the ABS sensor on the rear differential, I haven't had a chance to get under the truck to check this connection.

 

I doubt that is your issue, for grins, is this a 2 wheel ABS truck or a 4WABS? ( Do you have front wheel speed sensors? )

I have had the same thing happen, but it is also accompanied with a brake pedal going down, no fluid loss though. In my case, the ABS valve was allowing fluid past the needle.

 

2 wheel ABS.
The brakes seem to be working fine, no change in operation that I can detect.

 

Do your brake lights go on and off in conjunction with your dash lights...if so, check your multifunction switch on the steering column.

 

not sure if this helps at all... but, when my rear differential speed sensor went out, both abs and parking brake light were on full time, but my speedometer didn't work until going 25 mph.

 

Mine did the same thing. When the ABS light is on the ABS is off! The rears will lock up pretty quickly and it is definitely an eye opener to the person in front of you when they hear tire squeel and only see grill in the rearview
I switched out the pumkin sensor twice and that wasn't the problem. Mine turned out to be the switch on the brake pedal. It isn't just a brake tail light switch, it has about 4 sets of contacts. If one of them doesn't have a good connection the ABS comp thinks the brakes are always being pressed and goes into mindless mode, tripping the ID10T lights.
The switch is cheap but it is tricky to install. It comes pinned in, DO NOT REMOVE THE TRAVEL PIN!!! until it is installed.
Install the switch on the bracket and with the brake pedal at normal rest pull the travel pin. The plunger will pop out and set the switch for the correct adjustment.