Ok, I have had this '94 JGC Limited for about 5 months now and every since I had bought it the ABS light has been on, I decided I am ready to have a look see and hear from some people what COULD be the problem(s).
With the ABS light being there on there are no noises of any kind, such as the ABS trying to work, I have drove down the road and jammed on the brakes hard at about 25MPH and all that happened were the wheels and tires locked up tight. No feeling or sounds of pump working. Just wondering where all the fuses and relays may be that would operate it. Also wanting to know how hard it may be to change any of this stuff. I found a junked JGC same year and ABS is working on it guy said I could have EVERYTHING for $45, test drove it in muddy conditions in a feild and seen they worked(thought that would be a steal if I can do this myself). That is the main question, can all this be done myself with maybe little help from my wife or friend??
Without taking it to a garage is there any ways of testing sensors or other important electrical components?? I was thinking that there is no power for the ABS to work? That would be where I would start first with fuses and relays, good idea?

Most ABS Systems need aScan Tool with ABS Cabibilty to retrieve codes and test the system , solenoids and in some cases Bleed the Hydraulic Control unit. I cant remember if you can access the ABS Codes Manually on a 94 JGC. It could be a number of things from wheel sensor to the Control Unit,even a blown fuse. The price is Very Cheap for the other ABS System Ive seen Control units go for 200 or more on E-Bay. Make sure you get the Controller Located under the Dash on the passenger side looks like a small ECM. You really need to find out the ABS Codes that are stored in your system. You should be able to Change the System out yourself. Just mark all the lines and connections. You might have a hard time Bleeding the System once you get air in the Hydraulic Control Unit. Every now and again you need a Scan Tool to help bleed the Solenoids to get all the Air out. Ill try and find my ABS Guide to see if you can access the codes with out a scan tool. Idont think you can.

Most likely it is one of the wheel speed sensors, but you will have to have the system scanned to know for sure. When the ABS light is on the ABS system is disabled so your abs system won't work. First thing I woudl do is check all 4 wheel sensor for cut wires, then check the ring tone gears on the axle for crud build-up.

I had changed the front only brake pads(gonna check rear tomorrow probably) and when I did this I took both the wheel sensors of the fron and just looked at them. They were built up with a lot of grime and dirt, so I cleaned them the best I could, looking at them they looked a little beat up to me, I figure that MIGHT be some of the problems. Ring gera looked ok though on both front wheels. Looks like they would have put them in a spot where they wouldn't get so much dirt and stuff on them. They are in the open. I am trying to do as much as I can due to a limited income ATM but would like for the ABS to work, I would feel safer with my wife driving it. Guess i will call up a garage and see how much it cost to have it put on the scan tool and then try working from there. Thought there might have been ways to use a multimeter and test things out though.

I'll give an update on this. Today I finally decided to check rear brakes today and see how the pads were. Well I think I have found a lot of my problems. I removed the rotor to inspect the parking brake shoes cause I have NO parking brake, AND what do I see, NOTHING THERE. No hardware or anything. I see why I have no E-brake and then start looking for the wheel sensor, it is not there either, so I see why the ABS light is now on. wheel sensor ring gear looks good though, so I think I will go to a junk yard and try to get everything I need to replace. Hate not having the E-brake working either.
Now my one thought is, "WHY on earth did the previous owner remove or have these removed?", any ideas why someone would do that?

well the parking brake on ZJ's were never really that good. the previous owner prolly got some noise out of the e-brakes and instead of putting new ones on they just decided to get rid of them. I don't know why they woudl get rid of the wheel speed sensor tho.