ABS/Brake Light On!

[Archive]

ROG:

I still haven't found the rooot cause. Based on the information in this thread, it's probably the Rear ABS sensor. As stated earlier, I have pulled and cleaned the rear ABS sensor, and checked/cleaned the CAB wiring harness. I still have the ABS and Brake dummy lights on, and my speedo stays at zero until I reach approximately 28 mph, then it zooms up to current speed. Oddly enough, my cruise control still works!

As suggested by another poster, it's time to take it in to the dealer and have it read by the scan tool. I'm postponing this because of all the mods I have done to the truck. I don't trust the dealer, and I've still got about 20,000 miles warantee left (on the Cummins). I'm considering risking the 35 dollars on a new sensor and replacing it myself. If it doesn't fix the problem, at least I'll have a spare #ad
.

I'll post results when available.

 

[Archive]

I was fourwheeling this weekend and had the same problem. I looked down and found both lights on. I shut down the truck, pumped the brake pedal a few times and started it back up... lights went off. Later in the day, I tried to park on a small incline. I pushed the parking brake pedal and let my foot off the brake, and the truck started rolling! I guess the rears were too wet or else so gunked up with mud that they wouldn't hold. The parking brake works fine now, and the lights have stayed off.

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Y2K 2500 4X4 5-spd Reg cab... Dark Garnet Red... Towing, Camper & Snowplow pkgs. Blaupunkt AM/FM Cass. & 12 CD Changer, Clearance and Tailgate I. D. lights
2" Daystar Front Coil Spring Spacers, 35x13. 50R16 M/T Baja Claws, 16x8 black Rockcrawler wheels,
Bushwhacker Extend-a-Fender flares. Thinking of adding a Skyjacker 5" double flex lift system.

 

[Archive]

... As stated earlier, I have pulled and cleaned the rear ABS sensor, and checked/cleaned the CAB wiring harness. I still have the ABS and Brake dummy lights on, and my speedo stays at zero until I reach approximately 28 mph, then it zooms up to current speed. [/B]

Another thing to ask: is your ABS engaging when you apply the brakes when going under 28 MPH? Does the speedo also cut out at 28 when slowing down?

If it truly is the sensor, the CAB would interpret the 'cutting out' at 28 MPH as a sudden change in the rear wheel speed and engage the ABS. If the ABS *isn't* engaging, then the CAB is seeing a good signal, if the CAB is functioning properly.

Try driving at, say, 50 MPH, then mash down on the service brake. Real hard. The ABS should engage (if you don't have any load in the back. The rears should lock up even easier if you pump the tires up to the max (80 PSI?) to reduce tread contact. If the ABS refuses to engage, you may well have a faulty CAB.

IIRC, there's also a connection or two under the truck in the rear sensor wiring. A dirty connection here could reduce the signal as well.