Intermittent ABS light and Airbag light

So, seemingly out of nowhere, my instrument cluster will ding/chime and the ABS warning light and the red brake warning light will come on for about 1 second. It never stays on continuously and sometimes you have to be watching close to even see what it is. The chime is the same chime that annoys you when a bulb goes out. I have changed the front unit bearings for some Moogs ( that's all Advance had in stock at the time), but that's been about a year ago. The only other thing I did was change the rear end gear oil to Amsoil Severe Gear 75W-90 the night before a 5 hour road trip. Come to think of it, the problem first started on the trip, but I can't figure out how in the world a simple gear oil change could have any effect on it.

I had my friend hook up his Snap-on scanner up and there were no codes present for the ABS. I did notice a couple times that my speedometer would jump from 45-50 MPH very quickly (like it got hung up and then released suddenly), so I changed the rear end speed sensor and this made no difference. The problem still comes and goes intermittently. So I found my old unit bearings and swapped out the old ABS sensors onto the front, but one of the sensors was no good (which the scanner instantly found along with the ABS light being on continuously).
I have checked the connections at all the speed sensors as well as at the ABS controller. All the connections are clean with no corrosion, bent pins, etc. I can't find any damaged wires or any other external problem that might cause this.

Sometimes the Airbag warning light will flash on quickly along with the chime. This is also intermittent with no codes set for anything. My friend at a local Dodge dealer had the airbag recall done for me recently, and I asked him about the airbag light, but he said the recall wouldn't have anything to do with it. And he was right, it still happens sometimes.

I can drive the 40 mile round trip to my parents house and not have a single problem going there, but then it might ding/chime for the ABS 3 times on the way back. This is so annoying and I'd rather have it stay on continuously so maybe I could figure out whats going on!

Anybody have any suggestions and to what might cause this? ABS controller going bad? This truck has been a good runner, but it's had way more problems than my '03. If it had been a 4WD, I'd still have it.

Thanks,
Will

 

I have run into "brownouts" in ECM's that cause them to act up. Specifically with GM's ignition switches going bad a problem dodge has from time to time with the blower motor circuit going through the ignition switch. This said I suggest looking at the basics like cleaning grounds, test batteries, and use the scan tool to see what "voltage" the modules are seeing.

IMO the "jump" you are seeing in the speedo indicates a "wiggle test" of the harness situation. Something has an intermittent connection where a bump causes it to loose connection and then work again. The speedo jumps from the connection loss. You may be able to find the problem by wiggling the wiring harness. Concentrate efforts by connectors and grounds.

 

Thanks for the reply. I was hoping someone has had the same problem before and might know an easy check/fix. When works settles down some, I'll try to concentrate my efforts on narrowing it down. I'll start with batteries and grounds and see where it leads. Then on to the wiggle test to see if something turns up.

 

It could be crud on the speedo sensor at the rear end . Check the electrical connection too

 

X 2 on the rear abs sensor.

 

I already replaced the sensor and the electrical connection looked good. The wiring had no obvious damage, either. But I'll have to do the wiggle test on it and see what it reveals

 

I was looking at the procedure in the factory service manual for accessing the clock spring. Looks fairly straightforward as long as my steering wheel puller will work. What do I need to be looking at once I get to the clock spring? Is there an obvious set of contacts that I can clean? Or just an electrical connector? I'm willing to give it a try as long as I know what to do once I get there.

As an update, I've removed and cleaned/scuffed/dielectric greased all the grounds coming from the batteries (both sides of engine block, both fender supports and also cleaned the battery terminals/clamps very thoroughly). Nothing was loose or corroded. I've yet to drive it after this, though. Any other notable ground connections I should check?

The batteries are in good condition and are from 2012, and although I haven't load checked them, it starts just fine at 40 degrees outside.

 

I am very curious as to what you find out here...mine has been doing the exact same thing for YEARS now with no help from the dealer to figure it out. I have always though that perhaps it was the known broken or"cold solder" joints on the back of the gauge cluster causing connectivity issues, but perhaps it is the clock spring.

 

Thanks for the info, cerb.

Seafish, is it only the airbag light that comes on? Or is it like mine and sometimes it's the ABS light? (they aren't at the same time, though) Does the chime go off when it happens?

I was trying to figure out if there was a common denominator (besides being Daimler Chrysler POS) or if I was having 2 different problems. Funny thing is, the instrument cluster crossed my mind because of all the crap that runs through it.

Sunday, the ABS light/chime came on one time while going slowly through cow pasture, another time cruising down hwy at 55MPH on straight/smooth road, then it chimed another time with no warning light at all (could've been airbag light...but it happens very quickly). It seems completely random...nothing noteworthy triggers it; i.e.-- hitting a bump, turning the wheel, applying the brakes, etc.


Edit: Rockauto has the clock spring for about $57. Looking at the picture they have, it just looks like a couple of electrical connectors to clean/inspect. For the trouble to access it, it is tempting to go ahead and replace it while I'm in there. Although I hate to throw parts at it, it would eliminate that possibility. Thoughts?

 

My ABS light came on and it wasn't too far down the road that I realized my left front wheel bearing was out. I made it another 20 miles to my driveway, but I wouldn't have made it much further, for sure!