All

 

I seem to be having the common problem of my ABS and Brake light on my dash being on, so I am following the document below, and it seems that my 4WD light does not come on when I shift into 4WD (been like this for a while though), so I replaced the switch last night.  The truck will still go into 4WD with front tires pulling, but the light still does not come on.  I did test the switch and the 4WD light will come on when I have the wire harness connected and I use my fingers to hold the switch down, but not when the switch is mounted in the axle.  With this being said is this a different issue and I still may have a bad ABS sensor?  Any insight on further troubleshooting tips would be greatly appreciated.  Note I do not think it is the rear ABS sensor since my speed sensor is working.

 

 

Edited March 15, 20187 yr by striegel.t

On ‎3‎/‎15‎/‎2018 at 9:58 AM, striegel.t said:

 Note I do not think it is the rear ABS sensor since my speed sensor is working.

I had the same issue (though I didn't check the 4wd light). My speedo did in fact work, but my scanner indicated the rear sensor as the problem. I replaced it and it fixed the problem, though I will say that the harness and the old sensor looked perfectly fine when removed.

 

 

Thanks for the reply @mrclean, however I did fix the ABS issue earlier today and am just now getting to a computer.  I replaced the front passenger ABS sensor and the dash light turned off.  Now my next question will be about the 4WD light since the switch has been replaced.  Since I know the 4WD switch is good, if the light is not coming on, but 4WD is engaging does this mean the CAD shift fork is only partially engaging and not triggering the switch?  I would think if this is the case the vacuum shift motor or vacuum hoses could be bad or going out?  

Typically the speed sensors are to blame for ABS / Brake light issues. In my case it was the tone ring in the right front hub broke the spot welds and spun the tone ring free. There has been one member here that had a carrier bearing fail and the tone ring for the rear differential was out of view of the rear sensor so be sure to check your tone rings. 

Look for vacuum leaks or a bad diaphragm in the vacuum actuator for cab, you are correct it's not engaging all the way. I ended up putting a posi lock on mine so I could have 2 wheel drive low for backing up a trailer. Some people put a vacuum switch so they can toggle cad on and off. I like the cable idea better. But ideally I'd love to have manual locking hubs and  servicable bearings. I guess my front wheel bearings are kind of serviceable now since I put grease zerks in them but that also caused a problem for ABS light to come on, over greased I believe.

2 minutes ago, Dieselfuture said:

I put grease zerks in them but that also caused a problem for ABS light to come on, over greased I believe.

 

Actually, it causes problems when graphite in the grease fills the voids of the tone ring and then the tone appears smooth. So there is no AC signal created so now the ABS computer things the axle(s) are not turning. 

1 minute ago, Mopar1973Man said:

 

Actually, it causes problems when graphite in the grease fills the voids of the tone ring and then the tone appears smooth. So there is no AC signal created so now the ABS computer things the axle(s) are not turning. 

Yeah I know we've discussed that before and you might be right, but I've pumped so much grease through them bearings and out the sensor hole, it's as clean as it can get, still have same problem. The only time light stays off is when I clean tone ring with a vacuum and it's really cold out so the grease stays solidified and doesn't feel them gapps.

I look at it this way there is no reason to go messing with $250 dollar unit bearings attempting to make them better. My bearings lasted 150k miles each time. So if you look at this way you can go around the earth 6 times before they fail. 24,901 miles around the earth (six times around is 149,406 miles). It's not like they failing to quickly. 

 

It's the people with oversize tires and strange offset wheels that create issues with bearing life because of how the weight and wheel offset torques on the bearings. Now, these people whine all the time on how the front suspension is junk and nothing lasts. I wonder why...

On ‎3‎/‎19‎/‎2018 at 6:25 PM, Mopar1973Man said:

Typically the speed sensors are to blame for ABS / Brake light issues. In my case it was the tone ring in the right front hub broke the spot welds and spun the tone ring free. There has been one member here that had a carrier bearing fail and the tone ring for the rear differential was out of view of the rear sensor so be sure to check your tone rings. 

I need some help understanding the ABS/Brake light coming on. Long story short, I thought I was having a bearing or brake or U-Joint issue. I bought new bearings all the way around for each side and had a friend pull the tires and disc brakes off. Apparently the noise was a caliber sticking a little causing the pads to rub the rotor which sounded like the scraping noise when I turned to the right or left. He went ahead and put the new bearing in since we had them. On the left side the inner race was difficult to drive out. It caused the tone ring to fall off. I thought I had ABS brakes because they pulsed when I hit the brakes hard. Only problem is there are no wires or sensors to indicate what I was thinking. The tone ring was left off and now after starting my truck the dash lights stay on. I looked in the manual but couldn't figure out how it all went together. Do I need to pull the left side off and tap the tone ring back in place to get the lights to go off??????????????? Can't figure why my brakes pulsed like ABS if I don't have the system on my 98 12 valve. Thanks 

Greenlee your 1998 does not have no stinking front ABS Junk

 

Neither does my '99 

 

 

 

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Edited March 22, 20187 yr by GSP7

@Greenlee, I just replaced my Power steering pump (@ the same time as my Vacuum pump) and I swear since I have replaced the pump if I get even a little bit aggressive with the brake peddle it seems like the ABS is going on.  Mind you mine is a 99 & it does have Rear ABS, so Im not ruling out that there is an ABS issue, but................. the only thing I have changed is the pump......  

 

Bob

 

8 hours ago, GSP7 said:

Greenlee your 1998 does not have no stinking front ABS Junk

 

Neither does my '99 

 

 

 

.

 

7 hours ago, Bobalos said:

@Greenlee, I just replaced my Power steering pump (@ the same time as my Vacuum pump) and I swear since I have replaced the pump if I get even a little bit aggressive with the brake peddle it seems like the ABS is going on.  Mind you mine is a 99 & it does have Rear ABS, so Im not ruling out that there is an ABS issue, but................. the only thing I have changed is the pump......  

 

Bob

 

GSP7, no junk on the front wheels just like you said. Drivers wheel has a tone ring and the passenger side has none. Once I started driving it both ABS and Brake lights turned off. I looked at the tone ring that fell off the passenger wheel and it has cobwebs between the gears. No wires or sensors any where in sight. It's strange how it seems to pulse when I hit the brakes hard but that could be me fighting to hold the brake pedal down. Thanks for setting me straight, one less thing to worry about.

 

Bobalos, mine acts the same way and it might be a characteristic of my trucks braking. I put National Bearing back in the front both sides, well I didn't but a friend did it for me. The can of grease I bought will out live me, hard to believe it only takes a small amount of grease to pack between the rollers and the distance it will go with good maintenance. Didn't think it would turn over this morning on my way to a doctors appointment. It cranked and I later took it to get 2 new batteries since the ones I had were bad. I don't know how but it seems to drive better. Who ever had it before me put 2 smaller batteries (foot print) and a heck of a lot less cranking amps.

Appreciate the information

7 minutes ago, Greenlee said:

It's strange how it seems to pulse when I hit the brakes hard

Your rotors are worped 

3 minutes ago, Dieselfuture said:

Your rotors are worped 

Riddle me this one. My brake and ABS light are both on and have been for a while. Never felt any pulsations prior to the lights being on but now have those pulsations under hard braking but I know the ABS is not working because I can lock all four wheels up. ???

@dripley it sounds like you may have two problems one related to warped rotors the other to abs, but this is just my speculations.

I have witnessed where pulsation/ vibration will come from the rear drums not front rotors.

This pulsation seems more rapid than the rotors a turning. Kind of odd for warped rotors.

3 hours ago, Dieselfuture said:

I have witnessed where pulsation/ vibration will come from the rear drums not front rotors.

 

So have I on my 1996 Dodge Ram 1500 I've got to replace the rear drum on the next brake service. 

On 3/21/2018 at 2:41 PM, Dieselfuture said:

Look for vacuum leaks or a bad diaphragm in the vacuum actuator for cab, you are correct it's not engaging all the way. I ended up putting a posi lock on mine so I could have 2 wheel drive low for backing up a trailer. Some people put a vacuum switch so they can toggle cad on and off. I like the cable idea better. But ideally I'd love to have manual locking hubs and  servicable bearings. I guess my front wheel bearings are kind of serviceable now since I put grease zerks in them but that also caused a problem for ABS light to come on, over greased I believe.

@Dieselfuture thanks for the recommendation, I will start looking into leaks this afternoon.  As for your cable posi lock, I like that idea, or a CAD delete kit with manual hubs, but that will take a bit of saving up for. As for checking the vacuum leaks, does anyone have any tricks to help find these easily?   

On 3/22/2018 at 7:18 PM, dripley said:

Riddle me this one. My brake and ABS light are both on and have been for a while. Never felt any pulsations prior to the lights being on but now have those pulsations under hard braking but I know the ABS is not working because I can lock all four wheels up. ???

 

FWIW, I have been able to lock up the breaks on my truck since it was new.  the ABS just pisses me off, because it relieves pressure for a second, then if you keep pushing on the brakes it locks them up.  I flat spotted 2 sets of tires because of this (early on in its life).  I learned that I cant go from a bike to the truck & expect them to stop the same.  LOL. 
 

BTW, Im with you on the warped rotor thing.  I have had warped rotors on this truck & know what they feel like.  this is MUCH higher frequency & not speed dependent. 

 

It just seems super strange that its started happening since I put in the new PS pump.  I might stick the old one back in just to see if it goes away, but that sure is a heck of a lot of work, to test a theory........ 

 

Bob

 

1 hour ago, Bobalos said:

 

FWIW, I have been able to lock up the breaks on my truck since it was new.  the ABS just pisses me off, because it relieves pressure for a second, then if you keep pushing on the brakes it locks them up.  I flat spotted 2 sets of tires because of this (early on in its life).  I learned that I cant go from a bike to the truck & expect them to stop the same.  LOL. 
 

BTW, Im with you on the warped rotor thing.  I have had warped rotors on this truck & know what they feel like.  this is MUCH higher frequency & not speed dependent. 

 

It just seems super strange that its started happening since I put in the new PS pump.  I might stick the old one back in just to see if it goes away, but that sure is a heck of a lot of work, to test a theory........ 

 

Bob

 

Never could lock mine until this last time the lights came. Flat spotted all 4 tires that were fairly new, 20k on them maybe. They drove kinda funny under 20 mph for a good while. All better now.

 

The ps pump does supply boost to the brakes, could be the culprit but I would not know.