Another ABS/BRAKE light question

[SBradshaw]

Alright guys here is another question about those dang lights. I have a 97 3500 5sp 4x4 with RWAL brakes. When I start the truck and sit there both lights will come on... if I start and pull away the lights won't come on till I come to a complete stop. Sometimes when I press on the pedal and the lights (brake/abs)are on it feels like the brakes release and it takes more pedal pressure to stop the truck. I don't think it is the rear wheel sensor because the speedo works fine all the time. Before I start throwing parts at it I thought I would throw this to ya'll. Thanks for the help!

 

[lschultz]

Not much help but go by the dealer and get them to hook up there puter to it and see if it shows anything. When my sons abs light came on in his 99 I figured it was the sensor in the diff but wanted to make sure so they put there puter on it and thats what it showed. Didn't charge anything either. Them sensors and all that high tech stuff they got on them now cause some weird problems.

 

[Koa Man]

My 96 auto was doing that, got progressively worse, till lights just stayed on all the time. Found a small hole in one of the vaccum lines when changing the fuel filter one day. I just duct taped it and lights went out. Been over two months now and lights have not come back on (except when it supposed to).

 

[Dieselnerd]

My ABS/BRAKE lights were caused by the sensor in the differential. I don't know if the '97's take their speedometer signal from a different place or not but my speedometer gets its signal from the rear of my transfer case not the differential.

 

[MikeR]

If your problem goes away with the engine pulling away at a higher prm, then I would say it is a vacuum leak. I have found the rubber connectors on the tees along the firewall soft and falling off on trucks I have worked on causing vac leaks.



-Mike

 

[SBradshaw]

Hey guys... I replaced the sensor in the diff. and still no good. Is there a way to get the codes from the computer? I also tried finding a vacuum leak but no luck. Could the brake booster or master cyclinder be causing the problem? If I start driving as soon as the truck is started the lights will not come on but as soon as I stop the lights come on. Or if I start the truck and just sit there the lights come on without ever hitting the pedal. And on occassion when stopping the brakes feel fine then all of a sudden its like the pedal goes to the floor and the truck barely stops. This dang problem is driving me crazy and from what I have seen alot of other people as well. Again thanks for any help.

 

[osmith]

ABS/Brake Light

Mine does this as well, but only in the winter or if I've been down a real dusty road. In the winter it must get froze up and in the summer heavy enough dust will make the lights go on as well. I'm dumbfounded as the rest and almost every guy I know who has a 98 and < has the same problem. I'm pretty sure mine is not a vaccum leak, due to its occurences, but then again I could be wrong.

 

[MikeR]

pulling codes

To get the lights to flash you a code, you have to ground out the connector under the dash. Look under the dash along the bottom of the knee bolster almost to where the knee bolster meets the kick panel, you'll find a black-single pin connector with nothing plugged into it. Get a piece of jumper wire, and with the ignition switch in the 'on' position, ground the connector. The abs light will start flashing. It will start with one long flash, followed by a bunch of short flashes, then start all over again with the long and short flashes.



Post on here what flashes you find, and I'm sure one of us with a shop book will decipher what it means.



-Mike

 

[SBradshaw]

Thanks for all the help... found the problem... it turned out to be a frayed wire that goes to the rear wheel sensor. Again thanks for the advice.