Trying to locate and replace the ABS sensor on my 1994 Ranger 5sp 4.0L.

Where is it and how do I get to it?

Thanks.

 

This is 3S/3M system, two WSS on front wheels and VSS used for rear axe speed monitoring.

some trucks had RABS (1S/1M) system. VSS only!!!!

what code do you have?

ABS light may be caused with many codes, like broken abs wire, bad sensor, air gap, bent/damaged phone ring, ABS pump, valves (there are 6 valves) and many other problems. not so easy to find w/o scanning codes.

 

Don't know the first thing about the codes or how to access them. I only know that the brake light and abs light come on as soon as I touch the brakes and it actually slid the front tires on me under braking that normally would not have caused that. Just figured the sensor would be the best place to start but I don't know where it is.

 

look, to read ABS codes you need ATE tool ore more sufisticated OBD-II scanner that reads ABS codes.

ATE makes units for both EU and USA market and they have k-line and SAE J1850 links for both the markets, but as I can see k-line pin is not used on OBD-II trucks and as I know this is pre obd-II vehicle and may be there is no diagnostic line for puling cofes, i'm not sure and may be there is only one way to pull codes - throught ABS unit main connector like on early ABS equipped semis.... so that's why dealers can pull ABS codes on early trucks.

well, but symptoms you say about do not look like ABS sensor fault.

Do you have abs light on and then off when you turn ignition on? if yes, ABS unit is powered and WSS are monitored constantly. So if you have broken ABS sensor wires, pole ring wobble, air gap, rattle and on later units - different tires you will get ABS light.

No ABS light - sensors are OK!

But what happens when you apply brake? ABS pump starts and unit is ready to drop pressure if wheel skids. but do you hear ABS pump motor sound? No? may be ABS pump is faulty! yeah, early ABS systems had no continious ABS motor and valve motor test. no ABS pump code, ABS light code till you apply brake and no valve code till ABS unit apply valve to unlock wheel.

So first of all check ABS power supply for corroded connectors, corroded/faulty fuses, if they are ok check abs motor voltage when someone apply brake, got no voltage - bad MOFSET inside unit, else - no current - may be brushes inside motor pump are worn....

I call this way manual diagnostics.

I'm not sure, but bosch/knorr/bendix ABS units had blink codes, like Wabco too, ATE had no blik codes and w/o scanner the primitive AVO meter is used.

abou WSS/VSS - resistance from 700 to 1800 ohm, voltage at 3-5 MPH - 0.9-2V, but no voltage fluctuations becouse it indicates bad pole rings, bad bearings, rattele ore air gap.

Modulating valves - 30-180 ohm, ABS motor - 5-20 ohm.