Guys Im getting a tad frustrated. Begging some help again! Last week my ABS came on intermittently. When this started my cruise control stopped working. What I did first was drain the rear fluid and clean the existing VSS. Once I did this the speedometer was worse than it was before about jumping around. The ABS light remained on. Went to autozone bought a new VSS and installed. The jumpy speedometer has cleared up but the ABS light still comes on right after start up and stays on. And cruise control still not working. The brake light does not come on. All brake lights come on when the brake pedal is depressed. I visually see no leakage of brake fluid anywhere. The fluid level remains constant so I assume there is no leaks as the level would be falling. Couple of things Im curious about. If the ABS light is on does that trigger the cruise control non operational or can the ABS come on and still have a working cruise? All pads appear fine and adjusted. Is there some sort of "brain" module for the ABS? If so where is it and can it be tested somehow. I have read in some posts about a brake pressure switch on the master cylinder. Is this an easy replacement or does this come when you purchase a new MC? Any suggestions would be most appreciated as I really dont want to go to the brake shop and have these guys just start replacing parts! Thanks Maxx

 

Sounds to me like your ABS Hydraulic unit has gone out. It is on the inside of the driver's side frame rail right below the firewall. My ABS light was on when I bought my truck so I replaced the sensor in the rear end, this did nothing so I just took the bulb out. Replaced my ABS unit and the line running from it to the master cyl. Fixed my problems.

 

Will a tripped ABS light keep the cruise control from working?

 

Does your 3rd brake light work above the back window IIRC somewhere there was a post about a burned out 3rd brakelight affection cruise control.

 

Yep all the lights work including the 3rd? I did not check to see if the blinkers were working? Headlights and parking lights were fine also.

 

I am not sure if the RABS can have an effect on the cruise but maybe.
If you look under the dash, probably near the parking brake you should find a black wire with an orange stripe and a single connector. This is the RABS diagnostic connector. With the key "on" and the ABS light on momentarily ground this connector and the ABS light should blink out an error code. Should be, from memory, between 1 and 12. If you can get a code it will help to pinpoint your problem.

 

Thanks a bunch! When I get home I will scout around for this wire. Maxx

 

The RABS sensor a.k.a. VSS feeds a signal to the PSOM that sends a signal to the PCM and CC.
IF the RABS is malfunctioning the CC might not work.

Test:

Verify the key is in the RUN position (engine does not need to be running). Next, locate the black RABS II diagnostic connector. The diagnostic connector has two mating halves (one of which has a black/orange wire connected to it). Disconnect the two halves.

Attach one end of a jumper wire to the black with orange stripe wire side of the diagnostic connector.
CAUTION: Care must be taken to connect only the black/orange stripe wire to ground. Connecting the red mating connector wire to ground will result in a blown fuse.

Momentarily ground the other end of the jumper wire by connecting it to a good chassis ground for 1-2 seconds. Grounding this wire should start the yellow REAR ABS warning light flashing. If grounding this wire does not start the yellow REAR ABS warning light flashing, go to the Symptom Chart.

The code consists of a number of short flashes and ends with a long flash. Count the short flashes and include the following long flash in the count to obtain the code number. For example, three short flashes followed by one long flash indicates diagnostic trouble Code 4. The code will continue to repeat itself until the key is turned off. It is recommended that the code be verified by reading it several times. This code will be used later for system repair instructions. It should be written down for future use. Diagnostic trouble code 16 indicates that the anti-lock electronic control module detects normal system operation.

Diagnostic Trouble Codes, Erasing

The last step of the System Pre-Check always includes clearing the Keep-Alive Memory (KAM). To do this, simply turn off the ignition while the diagnostic connector halves are separated as described in the procedures for obtaining the diagnostic trouble code above, after which the diagnostic connector should be reassembled to provide KAM power to the anti-lock electronic control module. If at this time a valid code has been obtained, go to the appropriate pinpoint test for that code.

 

I have been all over this truck trying to locate this black & orange wire? I also cant find the control module? I assume the module is under the hood somewhere attached to the firewall. My 1/2 azz manual says it is just inboard of the master cylinder on the firewall> I dont see anything that looks like this module. Is the black/orange wire inside the cab or outside under the hood somewhere? A picture is worth a thousand words. I can find the ABS valve on the rail and I know where the VSS is but for the life of me I cant seem to find this diagnosis wire or module. Any links which might help find want Im looking for, BTW this is a 96 F250. Thanks guys

 

It's connector 159 (C159) on the right side of this diagram.
Behind the glove box, near RABS module.
.
.

 

Jim do you gain access to the wire and modlue from inside the cab or in the engine comartment and THANKS! for the picture its a great help.

 

inside of the cab, clipped right at the base of the dash under the glovebox

 

your problem is most likely the rabs valve, located on the frame rail right next to the oil filter. and the cruise is probably coincidence, my rabs valve is bad as well, throws an abs light for days at a time then goes away. my cruise always works. i cant see how the rabs valve would effect it. your cruise control deactivation switch is probably bad, located on the master cylinder

 

Thanks for the help guys. This weekend I will get into it!

 

Good info reps sent!