Last week I took my truck in because the brake pedal was slowly dropping to the floor when the brake was applied as well as making a clicking noise. They told me that both rear cylinders were leaking and needed to be replace (I knew about this before and just let them go ahead and do that because they needed to to diagnose the other problem). After that was done they said the master cylinder was going out and needed to be replace but they couldn't do that by the end of the day so I took the truck back since I needed it for the next week.

I took the truck back in yesterday and they tell me that the master cylinder is not the problem and it is in fact something with the ABS system. They disabled the ABS and the clicking and pedal dropping stopped. The truck stops normally. The tech said that none of the ABS wiring was in the correct place and asked me if a different cab had been swapped onto this frame. I assured him that it had not and that all the abs equipment was original.

So now the ABS system is disabled and the truck stops normally. Keep in mind I have RABS not 4 wheel. I'm not too concerned about driving it the way it is because RABS does not really help that much if the front brakes lock up. I guess I will be taking it back in next week but I was wondering if anyone knew what was going on with my truck.

Now that the abs is disabled the abs light is on as well as the brake light, however they were never on before the system was disabled. Any thoughts?

 

Brake light will come on if 1 its low on fluid, 2 parking brake isnt all the way up. Those are for normal operation. I'm not sure what they did.

Check the fluid and pbrake. As long as it stops well and makes no noise, ignore the lights.

 

I don't know if you read what I wrote correctly.

The lights never came on until the shop disabled the abs system. It stops normally with the abs system disabled.

 

If the ABS system is disabled, the PCM will trip an ABS light and P-Brake light to indicate this malfunction. If your ABS fuse blows, the same thing will happen. It is normal for these lights to be on if the system was disconnected or otherwise "disabled".

There is no noticeable change when the ABS system is disabled, other than the lack of pedal shudder upon hard or slippery braking. The Pedal shudder you felt before was normal operation of the ABS system, however it wasn't working at the right time. To me it sounds like either the signal is damaged, or the module itself is bad.

However, it won't do any harm to the vehicle to drive without the ABS system. I personally think it stops better without ABS in certain circumstances.

Have you checked the VSS? Are your Speedometer/Tripmeter/Odometer working? How did they disable the ABS system?

 

I'm not really sure what they did to disable the system because the tech wasnt there when I picked it up. They may have just taken the fuse out.

The speedo and odometer work fine but I have not checked the vss.

Do you know where the abs module is? and is there was way to check it. I know the vss is on top off the diff.

 

If your speedometer is working, your VSS is fine.

The ABS module is behind the radio bezel. It's likely they disconnected the harness to this module to disable it, if they didn't pull the fuse.

 

Ah yes I remember where it is now, I had to splice into a wire coming off of it for my truspeed calibrator a long time ago. Thanks

 

My point was check the brake fluid and pbrake. Forget about the lights till you get the abs fixed if you choose too.

 

The lights never went off, it was at a repair shop and they couldn't figure it out. They said none of the wiring was where it is supposed to be.