2nd Gen Non-Engine/Transmission BRAKE and ABS lights coming on

[Blakers]

Here I am with another question for the knowledgeable crowd:



Yesterday while plowing my driveway with my Ram, the BRAKE and ABS lights came on and I seem to have lost the rear anti-lock. The brakes stop ok and all four wheels will now slide on a snow packed road - I stuck my head out the window and watched.



After I shut the truck off and restarted it the lights stayed off and the rear antilock seemed to work. But today on the way to work they came back on again.



What could this be? Could it be that salt go into a connection somewhere? Could ice built up under the truck have pulled on the wiring to the rear end?



Thanks for your help. Sorry I have not been on much lately to help others - I lost my internet connection at work for awhile and don't have much time at home to be online.



Blake

 

[GFoley]

It might be your rear wheel speed sensor.

Mine did the same thing, I replaced it and all is well.

 

[Cooker]

Sensor and/or the wiring harness are likely culprits.

 

[Blakers]

Thanks guys. Everything under the truck is saturated with salt and there's ice and snow packed into everything. And it's 5 degrees out! Once it warms up a bit I'll wash her underneith and see what I can find.



Blake

 

[Dan_69GTX]

Pull the codes from the ABS computer and see what it says is happening.



It will at least point you in the right direction.



Dan

 

[Adam]

Been there...done that

DC just replaced my Computer Assisted Braking (CAB) module in the ABS system. I had the same symptoms you describe. The service manager says it's been a fairly common thing in the '01 and '02 trucks. I had a '99 with 4-wheel ABS and never had a problem with it, so it might not apply to you. Just another thing to worry about.



-Adam

 

[Cousin Billy]

Lights on-lights off

Blake,



This might be purely coincedental, on my 96 (hydra-boost, not a vacum booster) the same symptoms appeared. I found a very small hole in the plastic vacum line near the vacum pump. Fixed it and the ABS and brake lights went out and the rear wheel ABS

was functional again.



Either way, all is well again.



Good Luck,

Cousin Billy

 

[Dan_69GTX]

Look at this post again made me realize something



You said you were plowing - does that mean you were in 4 wheel drive?



If so your RWAL system should be disabled!



When in 4x4 the power that lights the "4x4" lamp also tells the computer that you are in 4 wheel drive. When this occurs the computer is supposed to disable the ABS system.



Dan

 

[rnolen]

I had this problem with my old 93 cummins. I replaced the speed sensor and all was fine. Seems to happen to alot of the dodges. Now I have a 97 and am working out the kinks. hope this helps

 

[Blakers]

Dan, would their be codes set if the "check engine" light did not come on? Yes I was in 4 wheel drive, but the lights should still not come on. It may be something to do with that though. Everything is covered with packed snow, ice and salt, so anything could happen under the truck.



Cousin Billy, I thought I'd check the vacuum with a gauge when I get time. I've been working all weekend and got stuck doing a double yesterday. I have not had time to think of it much. But today on the way home from work the lights went out and the abs seemed to work. Then the lights came back a little later. So who knows?



First thing I'll do is hose the bottom of the truck off with hot water and look for bad connections. Then go from there.



Thanks guys.



Blake

 

[midwestdually]

check the wiring harness on the rear differential ... mine just did the same thing that you are talking about and the harness was disconnected and beat to s**t..... or your speed sensor... both on the rear diff.

 

[jrollins]

my 2001. 5 does this also, the codes i have pulled out are brake foundation and controller timeout. i replaced the rear wheel speed sensor (due to failure: speedo stopped reading) and brake light switch to correct the problem, no go it still came back on and off for a while, finally started getting the light relay in the fuse box in the dash to make a vibrating noise, unplugged the relay and plugged it back in, no more noise from the relay and no more ABS light problems. . P. S. dealer never had a answer to what caused the issue other than the codes generated meant the brake lights were on to long?

 

[Dan_69GTX]

Blakers



The ABS computer does NOT use the check engine light - it uses the ABS light. I can't remember off hand how I pulled my codes - check the service manual - that is what I did.



Your right - the ABS light should not come on unless it detects a problem.



Dan

 

[Blakers]

Still trying to figure this one out. This is the first time I've had to work on it and it's ABOVE FREEZING! for the first time too. Washed the under side of the truck off good so I could check it out.



The wiring to the rear end looks good and I sprayed contact cleaner on the connection to the speed sensor. Looking at the book now too.



How much are the speed sensors (on rear axle) and are they easy to replace? This is a 95 with the speedometer sensor on the rear of the transfer case.



Thanks.

 

[Blakers]

I guess the best thing to do next - according to the manual - is to run a diagnostic code check on the braking computer. There's a plug under the dash for this. Has anyone done this? Suggestions?



Thanks.

 

[ox1]

Yep, my brake and ABS lights have been on for yrs too now. That may have something to do with the fuse that I pulled out of the left side dash.



I had a VERY bad experience one day with my gooseneck hooked on. I had to brake extra hard for whatever reason. The ABS kicked in and started pulsing. This was NOT a good thing with 20K hooked on the back! I fixed that problem! I know how to regulate my brakes, I don't need some blessed 'putor to do it for me.



The ABS light has started to not come on just recently now. One day soon maybe they will both burn out and life will be better eh?

 

[Cooker]

ox1,

Good point. Towing heavy loads and ABS sometimes do not mix very well.

 

[Blakers]

Originally posted by ox1

Yep, my brake and ABS lights have been on for yrs too now. That may have something to do with the fuse that I pulled out of the left side dash.

I have a feeling though that my rear brakes are not getting full pressure as they were before. Could a bad sensor tell the valve to the rear to stay half closed all the time?

 

[Blakers]

I just ran the diagnostic test and it says it's Fault Code Number 9 -- "Speed sensor wiring/resistance (usually high reading). "



So, does this mean it's my speed sensor?



Thanks

 

[Texas Diesel]

Do I have the same problem here? When I am in 4wd and get ONE of the front tires to spin the ABS light/brake light come on and stay on till you shut down and restart. The dealer told me it was because the ABS saw the single front wheel spin as a system fault