Hey guys - new problem as of last night on the way home from work...
2003 Ram 1500 Hemi 5.7 with about 175000 miles.
My abs is coming on when I break at low speeds. The pedal pulsates like I was on ice. No ice, clean, dry roads. (I have a 300lb load in the bed and its making it a bit scary to stop). High speeds no pulsation, just below 10mph. Where do I start? Pads and rotors are fine, I have plenty of fluid ect.

Thanks.

 

Pulses or vibrates? I suspect you have one or two warped rotors.

 

More of an ABS pulse. Same slow breaking and pedal feel as ABS, I'm almost sure its the ABS kicking in...almost :-)

Breaking is delayed, pedal pulse and slowly moves towards the firewall as the truck comes to a stop.

NOTE: I just remembered another weird thing...not sure if its related. So this breaking issue happened yesterday evening. Today, on the way into work, my cruise control will not work properly. When turned on, the truck speed surges and slows repeatedly. Like it was coming on the gas, off the gas, on the gas, off the gas. It won't hold a steady speed. With large generators we would call it hunting.

 

I think that it might be time for new ABS/Speed sensor(s)... is your truck 4x4 or 2x4?

With that many miles, if you haven't done it recently I would do a full flush of the brake system and fill it with brand new brake fluid....

After so many heat cycles the fluid in the caliper will break down and begin to cause deposits to form and almost solidify inside the lines and caliper/pistons.

I'm still very sure that your ABS/Speed sensor(s) are to blame b/c that is the only thing that would cause the cruise control to have some issues. It's always a good idea to get the preventative maintenance out of the way though.

 

Thanks! Its 4wd. How many sensors do I have and where are they located? I changed my brake fluid at about 120000 miles.

 

I believe you have at least 2 sensors... One on the output shaft from the transmission and one on the top of the rear differential.

Someone correct me if I am wrong, but that's where I am 99% sure they are located.

Your brake fluid should be fine if you've changed it that recently.

 

Thanks - I crawled under last night...nothing obvious. I'll have to give the dealer a shout and replace the sensors...

 

I finally got around to fixing this problem. It turned out to be the rear diff ABS/Speed sensor. It was cracked right down the middle. I changed it out and all problems were fixed. No more random ABS coming on when I brake, my cruise control works, and my speedo isn't jumping around.

 

To the op FYI the 4x4 Ram 1500 abs sensors are located in both front hubs and one sat on too of the rear diff pumpkin.
Al.

 

ONLY IF equip'd with 4wheel ABS(optional) Otherwise, the Rams only have Rearwheel ABS. Any sensor on the front hub is a speed sensor.