Rear ABS Light on, 91 XLT

[mwatkins]

91 XLT rear ABS light has been on for a while (2 years), is there a common problem with this? I am thinking of just unplugging the light so I can stop explaining it to new passengers.
Thanks

 

[Byrd91]

Mine is on, no codes, rear antilock doesn't work, but I don't like antilock anyway. I might try changing the sensor, don't know though.

 

[parli22]

ABS LIGHT

My ABS Light when ON mine. It torture the hell out of me that I could figure it out. I replace the the sensor on the rear axle housing also replaced the ABS Valve.
It the sensor in the brake fluid that has gone bad. It when on mine and cost me a few bucks to replace and about 2 1/2 hours since I never played with the master cylinder before.

So get the sensir in the reserve check. I bid you it hthat

 

[asp84]

The Rear ABS system on the 91 Explorers is absolutely useless! It does not work.....even when the light is off. I had this problem before too. You can ground the ABS wire to get the codes from the RABS computer. (it is a seperate computer from the ECU) Hopefully you aren't trying to pull codes from the ECM computer.
The ABS computer wire is on the driver side in the cab, under the dash, near the main round connector. Check out a Haynes or Chiltons manual for exact location and procedure.
I solved my specific problem by replacing the RABS sensor in the rear axle. One bolt is all it takes to remove the sensor. ( I got the sensor from FORD, it was like $22......cheap for FORD!!)

Anyway, after replacing the sensor, the light went off, PROBLEM SOLVED!! Hope this helps!

Al

 

[expobronc]

mine did that for a while except the emergency brake light would stay on also. it wound up being some stupid valve stuck open. i went ahead and fixed it because of a scarry near rollover that i felt could have been avoided if the rear abs was working. i think it was like $225 to get it fixed, i should still have the reciept.

 

[asp84]

Remember the 91 explorers had Rear ABS only, where the 92 and up explores had 4 wheel abs. (which uses a PUMP to control pressure) The 91 Explorer system has a different but simpler system. Here is how it works. The front brakes lines run straight from the Master cyclinder to the calipers (no front ABS) The rear brake lines run from the Master cyclinder to a pressure regulator mounted o the driver side frame, then back to the rear drums. The RABS computer, which is under the interior dash controls this simple pressure regulator which receives imputs from the rear ABS sensor on the axle. The RABS sensor located on the 8.8in rear differential detects wheel motion, and sends it back to the computer, which compares it to the actual vehicle speed. In theory, this pressure regulator is supposedly supposed to release brake pressure on the rear brakes in a controlled release.

I hope you can tell that I have had to deal with this before. My suggestion to you is: Ground out the RABS test wire (as per the chiltons manual) and get the codes. Most likely the codes will mean nothing to you. (as they did to me) Since the system only has two parts you could replace, I started with the cheapest, and EASIEST.... The Rear ABS sensor on the axle. You just unplug the wire harness connected to it, remove one simple bolt, and wahlah, it comes right out. Start with that!!

Sorry for the novel, Let us know if that works!

A

 

[JDraper]

There is another, much simpler and cheaper possibility. If you haven't changed your fluid in a while, your fluid may have too high a water content. (Brake fluid is very hygroscopic) If this happens, it fools the abs sensor into thinking the fluid pressure is too low, turning on the light and turning off the system. I had this problem happen to my old '92 Sport, which only had the RABS system. When we pulled the codes, it read "low fluid" and "low pressure". Since neither seemed to be the case, we hooked up a manual pressure gauge to the system, and found that it read normal. We then completely flushed the system twice (had it done at Monro, they have a power flush machine), and it fixed the problem. Cost about $25 to have it done. HOWEVER, the problem did not go away immediately, it took a week or two because there RABS module is on a dead end brake line in the driver's side frame rail, and it took a while for the new fluid in the system to mix with the old fluid in the RABS module(not a lot of fluid, but that's where the fluid density matters).

asp84, I have to disagree with you about the RABS system being useless. When mine was out on my '92, the truck was very difficult to stop when braking and turning at the same time. It wanted to swap ends pretty quickly. I though the same thing when my light popped up, and I was gonna just yank the bulb, but after driving it for a couple of miles, I quickly changed my mind.

 

[asp84]

JDraper:
Hey, your welocme to disagree! I'm just talking from my past experiecne with RABS in FORD Rangers and Explorers. My RABS light was on for half a year before I fixed it. I live in the Rainy and very slick state of Washington, and it did not effect my braking performance or lock-up.
I guess I had your system.

 

[Mettler]

Im res-erecting a dead thread but I have some input.
The RABS computer reads speed from 2 different sources. If your speedometer cable is screwed and your speedo doesn't read the correct speed then it is going to get 2 conflicting readings. Thus confusing the computer and you get a light. I used to have a Ranger and when the rabs worked it worked great. It kept the truck from swapping ends very effectively. Now my explorer has an intermittent rabs light and functionality. After reading this thread, a theory has been confirmed for me. As my speedo is consistently off by 10-15 mph. So I'll be replacing my speedo cable soon.

 

[mcgufer]

Check the wiring, half the time I seen this problem at my shop it is caused by a broken or worn wire somewhere between the sensor and the frame.

btw asp84 my 92 only has rear abs

 

[Mettler]

Ok so I tried to pull the codes while the light was on. Wont give any codes! I ground the wire and the damn light just stays on solid?!!? WTH?