I have a 94 Dodge Ram 2500 2WD with an ABS & Brake light on issue. This issue appears intermittently; sometimes for a day and other times for a week or more. When this problem returns these lights come on without fail when the speedometer reaches 39 mph. This is the one 100% reliable piece of information about this issue I can bet on.

Pads, calipers, rotors, wheel cylinders, brake lines and wheel speed sensor have all recently been replaced. Master cylinder has been inspected with no issue reported. There are no leaks. Brake pedal does not drop. Braking action is good but I know I do not have ABS when the lights are on. I can reset the lights by turning the engine off but as soon as I hit 39 mph they are back on again. The speedometer works fine; ie no bouncing around of the needle.

Does anyone know what is the cause of this problem and how to fix it? I've had this truck inspected by 3 different mechanics and they cannot find the cause.

 

Just rear wheel abs or 4 wheel? Maybe inspect the tone ring in the carrier make sure it isn't gunked up or missing teeth. Otherwise, the connector jumper for the rear sensor is prone to failung, make sure the new sensor came with the short harness (6" or so) and make sure all connections are very clean. I believe that sensor runs through the big connectors behind the drivers wheel ( on later trucks anyhow) make sure those are clean as well.

 

This truck has only rear wheel ABS. Thank you for the information.

 

My 1996 Dodge truck brake ABS light came on. Up by the master cylinder there is a connector that can come unplugged when changing fuel filter hit it and it came off didn't know it till I got ready to crank it up and noticed ABS light stayed on.Plugged it back up and light went off. Just my 2cents might check it.

 

From the sound of it, your brake light switch is always on, doesn't mean your brake lights are, just the portion of the switch that controls the ABS.

This is from a 95 manual,