'04 Ram 4x4 ABS question

[RECHRGD]

I live in the sticks and with all the snow we had in December, that has not melted at all, my driveway has turned into about a 1/2 mile long luge run.  It's turned into solid ice and if it didn't have large berms on the side from plowing, I would not even attempt to go down it.  I've noticed that the ABS system does not appear to be functioning at all.  I've made the trip down and up both in 4wd low and 4wd high.  The manual does not say anything about the system being bypassed in 4wd and the ABS trouble light is not on.  The fuse for the ABS pump appears to be fine visually, but I didn't pull it to put an ohm meter on it.  I just creep down the driveway.  Do I need a certain amount of speed for the system to sense the slippage?  I just came back from my daily trip down to get the mail and had to pump the brakes manually to maintain any control at all.  Any ideas?  Thanks, Bob

[Chatt69chgr]

If the ABS in your truck is anything like the ABS in my cars then it only activates when you really hit the brakes.  You can feel the pedal modulate when this happens,  I don't think creeping gradually down an ice covered surface would activate the ABS.  The vehicle that I was speaking of was my wife's 2002 Camry and the ABS was real noticable in it.  I've got it in my 2005 Quad Cab Ram 4X4.  I THINK it activated once.  I am ashamed to admit this but I was driving down a 2 lane blacktopped road about 40mph looking off the road for old 2nd gen chargers and looked back up at the last second and slammed the brakes on.  Truck did stop just in time.  It scared me so bad is the reason I don't remember for sure if the ABS activated.  But I do recall that the wheels didn't lock up which made me think that the ABS had just saved me hitting the car that was turning. 

[Silver R/T]

ABS will only work when system senses brakes locking up when you're braking.

[Tigger]

Brake fluid apply pressure is modulated according to wheel speed, degree of slip and rate of deceleration. Sensors at each front wheel convert wheel speed into electrical signals. These signals are transmitted to the ABM for processing and determination of wheel slip and deceleration rate.

You might not be meeting the criteria for the abs to turn on .

[RECHRGD]

Brake fluid apply pressure is modulated according to wheel speed, degree of slip and rate of deceleration. Sensors at each front wheel convert wheel speed into electrical signals. These signals are transmitted to the ABM for processing and determination of wheel slip and deceleration rate.

You might not be meeting the criteria for the abs to turn on .

That's what I'm thinking also.  But, I took the wife's '06 Subaru Tribeca down a couple of days ago and the ABS did activate when it started to skid under the same conditions.  Could just be the difference between the systems in the two different vehicles.  Bob

[flyinlow]

The abs on my 04 ram does not do much in 4wd.  I think the system does mostly front/back difference which is limited in 4wd. Works o.k. in 2wd.

Not as sophisticated as a some car systems.