Got a little puzzle to figure out when I get back to the world. On the way into Anchorage to catch my flight to hell, my ABS and brake light came on when I hit the coast button on the cruise control to reduce speed. Brakes and ABS seemed to be working normally before and after. No time to do any trouble kind of shooting, had a flight to catch. Any Ideas on what to start looking at and for? I'll check for codes 1st thing. Not too long ago I replaced both rear brake calipers, everything has been working fine.

 

When this happened to me , it was the little speed sensor on top of the rear axle. Cheap part, easy to install. It fixed this issue for me .

I believe that another symptom my had then was that the speedometer needle would also jump around......

Dew.

 

See if your cruise works as well before you get too goofy on replacing parts.
The Brake light switch can pull this stunt if it gets out of adjustment, free check is to pop the switch out, pull the stem out a notch or 2 and reinstall to reset the switch.

If this is the issue the light wouldn't have come on until after 20 MPH or so.....

 

Rear sensor on top of pumpkin may be it. My 03 3500 was doing the same thing and was shooting code for that sensor bcause of a loose wire on drivers side under hood, under fuse relay center. Several wire bundles under there...look for black wire with orange stripe being loose ir corroded. That fixed mine.

 

If you are having several symtoms its more likely a wiring issuse than that one rear speed sensor. The wire that supplies that sensor starts at the fuse box like any wire but is rarely dedicated; that is it may supply power to more than one thing along its path therefore causing many different issues.

 

The plastic brake switch under the dash has many internal connections. If the switch is faulty then it can cause ABS/brake light issues, cruise control issues, etc...

 

My truck is self healing. When I got back to it this morning it was fine again. No lights when I started it and they haven't come back on sense. Go figure.

 

You must have muttered something about selling it.....

 

I did the rear sensor in the third member it was easy to do. My symptoms were intermittent.
I am now getting intermittent light and it seems to be connected to our emergency brake.

 

I'm not following what you're saying.....

 

If it is your ebrake only the brake light would come on. Try resetting your brake light switch and see what that does. Easy to do, twist to unlock the switch, pull the plunger out slightly, reinstall and it will set itself to the right length.

 

Sorry I have two things going here,I did my third member sender a few years back for the rwal.

The light now is just an intermittent one when the ebrake light switch sticks,I don't think the two are connected .

 

A year later, it did it again. Except this time on start up. It was very cold out (-zero) and the power steering pump and hydro boost unit where complaining about it. The thing is, everything was working normally. Speedo rock solid, cruise control fully functional, and the ABS system was working as advertised. When I went home that night, the lights blinked a few times after start up, then stayed off. I did have it parked in a nice warm hangar all day. Could low, or too thick fluid cause this? I did notice the PS rez a little low.