Found this switch under the dash today and it makes the abs light come on when you press it. What is this for?Attachment 21084Attachment 21085
What part of the dash is that button under? From what I understand that button can be used to get a code from the ABS system when the ABS light is on... and my ABS light is on...
95% of ABS issues seem to be with speed sensors.. some of the earlier ABS were rear wheel only and only had 2 sensors.. one on a front wheel as a reference and one on the rear diff.. the better systems have speed sensors on both rear wheels or all 4 sets of wheels..
you may be able to call thomas and find out what ABS module you have (by VIN).. and then can begin looking up diagnostic info for it.. some of them have an actual diagnostic connector you can plug a scanner into, others you shorted a couple pins together on the connector and that would trigger a self test and the ABS light would flash out codes.. the trigger pins sometimes wired to a dash switch or to the starter-engage momentary circuit on the key switch. so the close and open of the starter switch would trigger the test on engine start.. without knowing which ABS computer you have its hard to tell... there were / are lots of them..
The International buses I have been around the past 13 years have a row of lights on the module that will light up and help you pinpoint the problem. Will tell you front, rear, sensor, modulator, ecu. You can also buy a simple tester, Bendix #801869, that will plug into the diagnostic port and does the same thing, saves crawling under the bus and locating the control module. Typically what I find is bad connections where the wheel sensor plugs into the harness, if its showing a bad sensor on one corner I will unplug the connector and check the ohm reading on the sensor. If it shows around 1200 ohms then it should be good, then I wash out the connections with electrical contact cleaner, plug back in and reset the system. The control module and also the tester can be reset with a magnet so after you try a repair just touch a magnet to the end of the tester or on the module where it says "reset" on it and it will tell you whether you were successful or not. If the light stays out till you drive it over about 10 miles an hour then it comes back on then it could be a bad sensor, bad connection on the sensor, or I have seen the sensors back themselves out enough that they are too far from the tone ring and they cant get a reading. Hope this helps
I took my bus in for a government required inspection so I can get my plates for it and in the inspection the shop discovered that a piece of black tape was put over the ABS light so it couldn’t be seen. That would’ve been done by the school district. After searching yesterday I found ABS computer with the lights indicating the right rear sensor. Since I have to get the rear brakes and drums replaced (appt tomorrow) I’ll have them switch out the sensor. I’m working on the assumption the school district at least tried to fix this problem but stopped short to remove the rear wheels to change the sensor.
The maintenance records the school district gave me showed the front left ABS sensor was replaced in late 2016 and then readjusted early 2017 so I know they did do some ABS work themselves.
If I get a chance I might see if I can have a closer look. Does the wire just pull off the inside of the wheel or is there a trick to it?
Here are a few pics of a sensor. The little gold piece is a clip that holds the sensor in place. There is a thick rubber grommet where the wire passes through the backing plate that you have to push out to get the connector to come through the backing plate. The connector on the sensor is the one that I typically have a bad connection problems with and try to clean them with electrical contact cleaner.
Thanks for the offer to help, I had a look at it and the wheels needed to come off to get to the sensor. Since it was going in for brakes early this morning anyway I decided the best way to go would be for the shop to do it. Only a half hour more labor on top of doing the brakes.
So the shop replaced the abs sensor on right rear and the old one crumbled in the mechanics had but unfortunately the ABS module was still showing the right rear sensor fault. They flipped the 2 rear sensors around so the left was on the right and the right was on the left and the ABS module still said right rear. Now I’m waiting on a $1200 new ABS module I looked for a used one but couldn’t find anything and if I could I’d just go without ABS brakes but the government inspection requires the ABS to be functioning if it was manufactured with ABS.
So the shop replaced the abs sensor on right rear and the old one crumbled in the mechanics had but unfortunately the ABS module was still showing the right rear sensor fault. They flipped the 2 rear sensors around so the left was on the right and the right was on the left and the ABS module still said right rear. Now I’m waiting on a $1200 new ABS module I looked for a used one but couldn’t find anything and if I could I’d just go without ABS brakes but the government inspection requires the ABS to be functioning if it was manufactured with ABS.
Did you ever get this dealt with? I just got quoted $6000 to fix my ABS light; fortunately the mechanic also recommended that I not bother fixing it as long as I avoid driving it in icy conditions (which I'm never going to do anyway).
Yeah I had to buy the module and a couple little things to get it working - No problems since. If I had the choice I’d have just gone without ABS since I know how to drive, and will not have it on ice much. I wonder what could possibly cost $6000, other than replacing the whole system - sensors, wires, module etc... that’s just insane.
Yeah I had to buy the module and a couple little things to get it working - No problems since. If I had the choice I’d have just gone without ABS since I know how to drive, and will not have it on ice much. I wonder what could possibly cost $6000, other than replacing the whole system - sensors, wires, module etc... that’s just insane.
He said both modules (left and right) needed to be replaced, $2000 for one and $2500 for the other, plus reprogramming of the ABS module and labor. It seems that the welder I hired fried the whole thing (as opposed to just cutting a wire).
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