Engine/Transmission (1994 - 1998) need help ABS/Brake light on

[mattymac]

My dads 98 12v had the ABS/BRAKE light come on while just driving down the highway the other day, everything seems fine other than the speedo wont register till about 20mph, jumps up and seems fine, anything under 20mph and it falls to 0. I was thinking wheel speed sensor on top of the diff?? Tried to search but didnt give me any answers so I figured id check with the experts! TIA!!



Matty.

 

[B.G. Smith]

I had a 99 that did basically the same thing and it was the sensor in the differential. The side bearings on the carrier assy. were going bad and a bunch of small metal particles had collected on the sensor. bg

 

[mattymac]

checked the sensor, totally clean?



Would this be just a bad sensor?



Is there anyway to check it??

 

[PRohr]

bad sensor... . a new one will fix you up... had the same thing happen with my '98 and my wife's '99 Durango..... brake light comes on and then the speedo drops off or bounces around..... new speed sensor and all is good.

 

[mattymac]

picked up a new VSS and put it in the diff, no lights on anymore and the speedo works perfect agin! Thanks guys!!

 

[cfarrar]

What's a good place to buy the sensor and how much does it cost?

 

[mattymac]

I went to my local parts store which is HUGE! The only sensor they could find was totally diffrent and said it went into the transmission, kinda dissapointed in that. Went to dodge (across the street) paid 63 bucks for the sensor which was an upgraded piece with a new extended wire/plug setup.



I have the box out at my shop with the part number. One of the service guys said that he just changed one out last week for the same problem, should be a stocked part.

 

[AMink]

When mine went out on my 97, I think I got it at NAPA. Can't remember the cost, but it wasn't as much as the dealer. If you don't have a NAPA around, you can order them online.

 

[Reddog1]

Can the sensor be bad, and the speedo be OK?


Wayne

 

[mattymac]

Can the sensor be bad, and the speedo be OK?





Wayne

Depends, The speedo wouldnt register anything under about 15-20 mph, it would sit at 0 then jump really fast up to about 20mph then work fine after that (20 mph+) slowing down would give the same results, under 20 and the speedo would just quickly fall off to 0.



Never had an issue like this before with the speedo until driving down the highway and the ABS/BRAKE lights came on then the speedo started to act up below 20mph.

 

[Reddog1]

My speedo works fine, and always has. My ABS/BRAKE lights have been on for over a year.


Wayne

 

[Missouri Mule]

There is a ABS sensor on the differential check to see if connector is loose or dirty.

The lights will go on also if you have brake light out or vacuum leak.

 

[B.G. Smith]

My speedo works fine, and always has. My ABS/BRAKE lights have been on for over a year.





Wayne

The sensor in the differential is a simple Hall effect sensor that senses the teeth on the tone wheel which is mounted on the carrier assy. I would think it either works or it doesn't. If your truck has all wheel anti lock system then it could be one of the sensors in front.

the emergency brake switch wil also turn on the red brake light if it is not releasing all the way. bg

 

[Reddog1]

I am satisfied that the Ebrake releases correctly. I do have the all wheel anti lock system.

I guess I will have to just change parts, startig at the rear diff.


Wayne