How to uplug ABS Computer?

[Gizmo 007]

OK guys, I posted the other day about having problems with the Anti-lock brakes. Where is the Anti-lock computer located, and how do I unplug it?



Come on, someone has to know how.

 

[MCummings]

I would like to know also.



My "tone ring" is damaged in the rear-end, which makes the ABS engage under completely normal stopping circumstances.

Stopping a 2wd 3500 with just the front brakes not only requires excessive pedal pressure, but also wears out brake pads, rotors, and tires very fast.



I have skidded to a stop a couple times while trying to stop for a light that has turned red. This situation has lightly flat spotted my front tires allready. (front tires only have about 2-3K, rears have about 40K)

I need to disconnect my ABS Pump, even if it lights up the dash like a Christmas tree. My ABS "idiot light" has allready burned out.



Anybody have any Ideas?



MerrickNJr



P. S. What would be Cool, is a switch to manually turn the ABS pump on and off at will.

This would keep the rear brakes from engaging(for the most part) and would allow full application of the front brakes. (Kinda like a cheapo line-lock) Also would help during situations you know are slick, and would want the rear brakes power lowered. (My 3500 could use this, as it has too many tires out back for wet, unloaded conditions. )

 

[JAK]

Gizmo: I can't help you exactly locate what you need to disconnect because mine is a year older and only has rear antistop braking. You might look close to the master brake cylinder. Follow the brake lines out of it and you should find the ABS valve. You should be able to disconnect the wiring there or maybe reroute the brakelines around the valve. If I'm not mistaken, the 01s don't have a proportioning valve for adjusting rear brake pressure when unloaded. Everything is done electronically through the ABS controller.



MCummings: You can pull the fuse for the ABS system or unplug the RWAL valve. I don't have my manual handy so I can't tell you which fuse it is right now. You could also disconnect the brake lines from the RWAL valve and reconnect them around the valve. Your truck has a proportioning valve so it will reduce the pressure to the rear brakes if you are unloaded. Don't know how well there proportioned for the 3500s though. I don't know if the fuse idea will light up any other lights but it's worth a try since your ABS light already burned out. BTW how did you get that stupid light to burn out anyways? I would love to be able to keep my abs fuse in my glove compartment without having that light on.

 

[MCummings]

Dunno how it burned out, I just looked down, and thought I had been driving with the Parking brake on, so I pulled over, shut the truck off, and then hit the ignition back on, and when the PCM checked all the lights, the ABS light wouldn't come on anymore,, Musta been my lucky day



Maybe Fritz will jump in here, and tell which wire on the PCM could be grounded , or the like, to activate the ABS Pump.



Maybe like the "Mystery Switch" for the Torque converter for the Auto transmission guys.





MerrickNJr





P. S. If you pull out the ABS Fuse, not only will the ABS light, illuminate, but the "BRAKE" light will also illuminate.

Talk about having to do extensive rewireing to get the ABS pump deactivated, and still have the "BRAKE" light work with the parking brake.

 

[Bigramguy]

We have done a few ABS removals on a few different vehicles,just none on a Ram,and it's not just as easy as disconnecting the computer. It will still sometimes leave the ABS and brake lights on,and can cause other problems. I know that the ABS is disabled in 4WD,so adding a switch,and applying power to ABS module where it receives it's signal from the 4WD will disable the ABS. It would probably work on a 2WD as well if they use the same module,and you can tap into it like a 4WD.



I know around here,I CANNOT safety a vehicle if the ABS is not working or disabled. If the vehicle was originally equipped with it it must be intact. Adding a little switch would be unknown if you require an annual inspection,but would allow you to bypass it whenever you wish.

 

[Bigramguy]

Regarding the proportioning valve on the rear,you can get a brake hose from DC to bypass it and apply more rear brake. Really helps the front pads last longer,and overall braking power. If you have the larger rear wheel cylinders,you may want to add a manual proportioning valve,just in case. I find with the rear valve bypassed and the ABS off,the rear end will lock up in wet or snowy conditions. A few turns of the valve is all it takes to remedy the problem. I have it mounted just under the dash,so it can be adjusted while driving.

 

[JAK]

Bigramguy: My owners manual says that the ABS is not disabled in 4WD but is not very effective because you can lock the front wheels and they will, through the driveline, lock the rears.

 

[SHOOT1SAM]

Gizmo 007: Don't do it! Consider the orgasmic joy that the bottom-feeding lawyers would have with you if you were to be in any kind of accident and it is discovered that you have disconnected a "safety" device on your vehicle. No matter what caused the wreck, the court system will hang you out to dry if anyone ever finds out.

 

[Bigramguy]

I haven't read the manual,but the last course I took on the newer ABS sysems,there were NONE that I know of that worked in 4WD. There are some that have AWD,or viscous drives for the 4WD,that will allow ABS operation,but it just doesn't work right on most 4WD vehicles. I have driven one which would NOT disable in 4WD (due to a faulty 4WD switch),and let me tell you,it had NO brakes when you locked them up in 4WD.



I did some digging in my ABS manual,and according to this wiring diagram I am looking at for the 4 wheel ABS system on the Rams,there is a 4WD disable input on pin 8 of the ABS controller,should be a DK Green\Yellow wire,or Black\Grey wire,depending on the year. This would be the wire you would tap into to disable the ABS without any other side effects,except the 4WD indicator will be lit,even though you will not be in 4WD . I was incorrect in stating this wire should be powered,it must be grounded.

 

[Gizmo 007]

Thanks. I'll try the 4WD disable wire. I'd like the mystery switch if anyone could research the idea.



Any tips are still welcome. Forget lawyers, ABS is what will end up causing the wreck to begin with.



Is the ABS computer out beside the brake master cylinder? There is a box with 2 plugs and a bunch of brake lines. Just guessing?! Maybe Just unplug the two bundles of wire? I dunno. Just being ignorant here.

 

[JAK]

The device with all the brake lines is the ABS valve. Unplugging the ABS valve will light up the idiot lights on the dash and set fault codes. The abs controller should be nearby. There's not much you can do without the idiot lights except the 4wd idea.

 

[Ron Moss]

I've been having problems with my brakes,the front ones grab at slow speeds below 10 mph. The brake pedal will pulsate and you can hear the abs,my truck is a 99 3500 dually with about 43000 miles. There is a fuse block next to the master cylinder,on the left fender,take off the cover and remove the 40amp abs fuse. The lights will come on but the abs won't work. Only problem is that when you jam on the breaks the rears will lock up and the fronts won't. Maybe that is only a problem on my truck,I just put on new front breaks to fix the problem and it did'nt work so I removed the fuse for now. Try it and see what happened's

 

[dan_gilson]

For Ron Moss:



I too, had the low speed grab and pulse.

It was crap on the rotors. What had happened (but I could not prove it) was that DC over greased the greased points. This got grease on the rotors and warped them. Grease and brakse don't mix.



Suggestions: Brake clean NOW. Take truck to

some other shop and have rotors checked with

dial guage. If needed, have them turned "on the truck". This compelely fixed my problems. Best of luch on yours.

 

[Deezul1]

Well guys I dont know if this will help as my truck is a little older and who knows whats changed. My dummy lights wouldnt go off no matter what so I unplugged the ABS computer (RWALonly on this truck) it made no difference in driving and all the lights went out. The ABS puter on a 97 is under the dash directly in front of the shifter (5spd) with the plug at the top. Remove the knee bolster under the steering wheel and you can see it and reach the plug just barely. This is for information only I do not suggest you do this as it might get you in trouble with some d!mn lawyer someday. But it works.

 

[Gizmo 007]

Thanks again guys, I found the computer Deezul 1 was talking about. I'll look at it closer tommorrow.

 

[Gizmo 007]

Well, I can't tell what to unplug if anything. The computer under my dash has 2 plugs connected to it. I dunno, I can't seem to find the Dk green/yellow wire on pin 8. Is that pin inside or out under the hood?

 

[Deezul1]

The plug is on top of the puter and on mine was the one closest to the drivers side, it kinda hard to see in there but just reach in , grab and start wigglin. If there is 2 plugs do em both and if that creates a problem plug 1 at a time back in and see if the problem goes away. I ran mine for a year unplugged and the only change I saw was the dummy lights went out.