Dodge Ram ABS and brake light on

MillWeld · Feb 2, 2014

With the trailer electrically connected the dash lights come on about 30 seconds after starting the engine. It is a 95 1/2T, 4WD and has a Prodigy P2 brake controller and all was working well 3 weeks ago when I last used the trailer. All the trailer lights still work properly - just these dash lights come on 30 sec after starting. The last time this happened (a year ago) it was due to a short in the brake wiring. I corrected that and the problem went away. I have no reason to suspect brake wiring this time because the trailer brakes worked properly 3 weeks ago.

In generaal, what causes both these lights to come on?

Diamondpilot · Feb 2, 2014

Wheel speed sensor.

Chris

Egon · Feb 3, 2014

On mine the hydraulic splitter failure resulted in the same symtons.

I'd suggest you check your wiring first as three weeks ago isn't today. There are more than one or two items that can show the failure symptoms you have.

radioman · Feb 3, 2014

getting abs light on with brake light is most likely not the abs sensor unless you have combination issue with your braking system. First thing i would do is check the continuity of the abs sensors to rule that out on all four tires. if they are not open or one is showing a higher reading then other 3 then you got one with bad sensor. Otherwise you might have air in the abs block. I would take truck on grass or slippery surface and slam on brakes while moving to make ABS kick in so the air can work itself out of abs black. Do the brakes feel spongy afterwards ?? air.

dodge man · Feb 3, 2014

I agree with Chris, its usually a speed sensor. Does it only do it when hooking up a trailer? A lot of the Dodge trucks from that era came with only rear wheel ABS. Keep in mind what I'm telling you only fits for my truck but there is a chance it holds true for yours also. Mine did the same thing off and on for a few weeks and finally the lights just stayed on. Mine is a 3/4 ton 2004 Dodge. There is a speed sensor located in the differential, not on each wheel. This sensor can be replaced from outside the differential and costs $30 or less. Takes about a 1/2 to replace. It's a very common item to fail.

kenmac · Feb 3, 2014

I had this happen on my 95 ram after I ran over a curb. I disconnected the battery for a few min. I re connected the batt, The lights never came on again

MillWeld · Feb 3, 2014

It is good to know others have observed this - I will keep the info in mind. As for now, today the problem disappeared! I re-connected one of the trailers that showed the failure yesterday, and today ... no problem!

The only difference was yesterday the trailer had no brake wiring. I connected it to my truck to test lights/turn signals before I wired the brakes and observed the reported problem. After wiring the brakes today I re-connected to the truck for testing expecting to see the same problem but... NO PROBLEM!?? I did not re-test the second trailer - why risk ruining my success late in the day:laughing:

wmonroe · Feb 3, 2014

Maybe you got lucky and it was just the trailer brake wiring not being completed. However like has been said the wheel speed sensor on the rear diff is also common.