Antilock brake Explorer

Read your owner's manual.

The answer is that yes, the ABS goes through a self test, and the light goes out.

But don't trust me. Trust the owner's manual. If you don't have one, get one at a Ford dealer.

That tells you that the antilock brakes are not working.

Take the vehicle to someone who knows how to fix it if you want it fixed, like a mechanic or Ford dealer with a good service department.

Yeah, a service department at a dealer where they have people who know how to diagnose and repair these.

Jeff

Who checked for error codes and exactly how did they do it? (be VERY specific)

Is the master cylinder full?

my ABS light came on and stayed on. dealer replace a an ABS sensor, but I don't know all of the details.

it wasn't a high cost repair.

I bought a used 91 Explorer. The light comes on during startup then goes out (passes self test?). About a minute later it comes back on reguardless if the truck is parked, running, use the brakes, or don't and I can lock the back wheels up.

No error code in the computer. I fixed the 3rd brake light. The gear on the diff is fine. I replaced the sensor. The old one was also a replacement (looks like I'm not the first trying to fix it). The RABS cable seems good.

So the next swap out is the control box behind the dash. I found a couple of modules and none have any markings. Does anyone know what the antilock control module looks like?

I had the same problem with same symptoms. It was the sensor in the differential - a relatively high failure item due to it's environment. Easy & cheap to fix.

KC

ABS is a curse in the snow... my ecu needs to be replaced, and i wont bother.. the ABS is useless to me

Swapping out the control box is the stupist thing you can do.

Most likely it is an ABS sensor or the wiring to the sensor. You won't know which sensor it is unless you get the car scanned.

I had ABS on my van go on about a year ago. I got it scanned. The problem was the right rear ABS sensor. A new sensor from the dealer cost $115. It came with the sensor and about a dozen feet of cable that snaked around all all over under the vehicle. I replaced everything. The problem turned out to be a small break in the ABS sensor wires about halfway along that cable. I would never have been able to find it unless I had taken that entire cable out. That was why the automaker supplied the sensor plus cable. Sometimes their parts designers aren't stupid.

Ted

To answer the questions: Yes I have the owners manual and the Chiltons and the Haynes and the TSB notices. It also says the lights comes on to test the lights. Ford has also used Lucas charging systems in the past which ran systems through idiot lights so systems failed when the lights burn out. When the antilock light goes out, does it really mean mean it passed the test OR THAT IT FINISHED THE TEST??? The second time from last I took a car to a Ford dealer, they fixed the problem and broke two harness connectors doing it. An extra month in the shop. The last time I took a car to a Ford, I discovered that their highly trained tech forgot to reconnect one of the rear brake adjusters (while going down a mountain). Since the repair is not under warranty why would I want to go there? Except to pay them $200 to replace the sensor and have the problem come back a month later as listed in other messages. But as you recommended I have taken it to two mechanics. Both put it on their diagnotic machines, returned it, and told me nothing found, and don't stop in the rain unless I wanted to pay by the hour for them to trouble shoot the system. And I did take it to an "expert", my brother-in-law who is a mechanic for a GM dealership and drives a Bronco. He can't get his antilock brake light to go out either. Oh by the way, did I forgot to say that I am SAE certified. (So go back to chatting about Toyota gas milage.)

Yes there is fluid in the master cylinder. I have never heard of brakes locking up when they are out of fluid. And the brake trouble light is not coming on.

The codes were read with a snap-on reader. It reads 2 and 3 digit codes and displays sensors status which are repeated by the on-board computer.

The '91 has RABS which only has one rotational sensor found on the diff. The sensor has been replaced twice. However the cable may be the problem. It would be simpler to test the cable from end to end then pulling it out sections. But that would mean finding the other end of the cable (which is connected to the control module). I have found four modules behind the dash and none of their wiring matches the sensor wiring nor what the wiring diagram shows the module's wiring should be. Since I don't want to figure out which is the correct cable by running voltage though the sensor wiring because it might damage the wiring on the hydrualic part of the system. And since the modules only have partial part numbers. Would anyone know what the antilock control module looks like?

The ABS system on a 91 Explorer has absolutely NO capability to communicate with a computer, a diagnostic machine, a scan tool or a reader no matter who makes it. The procedure for extracting codes is to jumper the shorting pin to ground and count the flashes of the ABS light. (blink-blink-blink-blink-blink-blink = code 6 for example) Given what you've described so far, it's no wonder no one has been able to pull a code for you, for whatever reasons, they haven't managed to read and understand the procedures. Once you have the trouble codes retrieved, diagnosis is plain old volt and ohm testing with a DVOM.

Sorry, there is no such thing.

At its literal description, it most certainly will; wheel cylinder leaks, shoes are soaked and contaminated, that wheel will lock on wet pavement, the master cylinder may be low or empty (out of fluid).

Also, being low on brake fluid does set off a switch that when triggered will turn on the brake circuit warning light and block other ABS code extractions.

More likely is that the RABS valve (on the frame rail near the fuel filter) has gone bad and needs to be replaced.