Just wanted to say thanks to GregA for documenting the problem and solution.

I also had the Brake and ABS dash lights come on with no apparent fluid problems. I bought the NAPA ABS Differential Sensor (Part Number UP 530780) for $10.49 and it cleared my problem.

I wonder if replacing the differential had something to do with the sensor failing. I note that you just installed one, and I just had one replaced as well. The old sensor had a fair amount of gunk on it, but cleaning it and re-installing it did not solve the problem.

---
99 E-350, 12 passenger, V-10, 4R100, 4.30 Limited Slip, 72,000 miles

 

Huh, could be? Same with mine: covered with metal "dust" and a couple of pieces. It's magnetic; maybe metal particles due to the break-in of the diff caused the Hall Effect sensor to go loco...? <shrug> - GA

 

Reviving and hijacking an old post here that up to the solution, describes my problem. Both brake and ABS lights are on as described throughout this thread. I just had the codes pulled, and though I didn't record all of the different codes, the long and short of it was that all of the ABS wheel sensors were not communicating. This leads me to believe that I have a problem with the module. I would assume that if the RABS sensor on top of the rear diff pumpkin was bad, that the codes would have reflected that (and only that), no? So, assuming that it is NOT the RABS sensor, I wanted to check all fuses and relays that supply power to the module, before getting into a hefty bill at the stealership. I have checked all of the fuses (#1, #2 & #11) that have any reference to ABS, 4WABS, or RABS in the manual, and all are good. I checked the 60A fuse for the ABS module that is located in the power distribution box, also good. The only other thing that the manual refers to is a 4WABS relay. I have looked, but can not find any of the fuse box or power dist box relays that are marked such. Can anyone point me to it? And/or, does anyone have any other suggestions of things to check before I go to the stealership? BTW, I should mention that this is a '99 E350 w/4WABS. I had just replaced all brake pads shortly before (probably drove 300 miles) the lights came on. My guess is that either the ABS module is not getting power, or has failed, but I'd rather find an easier solution. Any help/thoughts appreciated.

 

Well, guess what. I don't know that anyone here will ever be able to explain it, but, I just went out and swapped the RABS sensor with one on another '99 E350 that I have here (that the ABS and brake lights were not illuminated on), just to eliminate that sensor as a possible source of the issue and low and behold, the ABS and brake lights are no longer illuminated on the van that had the issue and they ARE illuminated on the van that didn't have an issue, i.e. moving the sensors DID move the problem. So, the problem WAS the RABS sensor. How and why that would cause the system to code out that all of the other sensors were not communicating, I have no idea. But, if you have both the brake and ABS lights on your dash illuminated, replace the rear ABS sensor BEFORE you try ANYTHING else as you will likely be chasing ghost codes if you don't. I hope this helps someone else down the line.

 

These threads are great! I just purchased a 1999 Ford E350 RV with 30,000 miles. I'm currently going around and playing detective to try and fix everything and the forum on these lights being on helped a lot, thank you to the contributors! Without even looking at it I went down to the auto parts store picked up a ABS speed sensor that goes on the rear differential, replaced it, and voila! The brake light went off, the ABS light blinked and stayed on, I suspect that's another sensor that needs replacing. But nonetheless, that definitely needed replacing and it fixed the brake light problem.

 

That's a good thing, keep us posted on how it works out. This thread began over 14 years ago.

 

Hi, my name is Josef and I am a new member I have the same problem you have - As soon as I let my foot off the brake, it goes back on - please let me know what was your solution for this ..

Thank you and all the best

Josef

 

After removing and replacing rear dually wheels (replaced valve stems) on my 2000 E450, brake and ABS light came on. Gonna try replacing the sensor on the differential. Any other ideas what may have caused this to happen by just changing tires ?