Started out it wouldn't set over 50 now it wont set at all

 

If its 02 to 04 check for vac leaks. 05 n up its fly by wire. In all cases a starscan tool usually need to determine if one of many speed or abs sensors bad, or a tone ring. If you had that prior issue of cruise set my bet is front left abs sensor and or hub. But starscan is only tool I'm aware of to read all sensors to pin point area of failure.

 

No, he has an 03 hemi, it's still fly by wire, no vacuum cruise. Even 04's are fly by wire (who told you they were vacuum? only 3.7, 4.7 and 5.9 would be). Starscan does not read PCI bus, only CANbus. Need a DRBIII to go in there with. Did you go to the dealer recently, have your speedo adjusted or anything else? They incorrectly adjusted my speedo which caused my cruise to not work. Once I corrected it it worked correctly again. If not, then the most likely culprit is the aforementioned sensor in the hub.

 

Sounds like ABS/Speed sensor is going bad. Depending on mileage, check for play in the bearing itself. Might be time to replace the hub assy.

 

I was going by what I read on this topic in the forum in regards to fly by wire, vacuum, and starscan was also mentioned. If thats case stand corrected. Either way its a dealership diagnostic to be entirely sur. My cruise cuts out at 64 I looked on here for solution I'm just waiting till it dies completely or till brake job time. Whichever comes first. I narrowed it to my front abs sensor n hub

 

I had the same issue on mine. Would set but turn off anything over 50-55. When I replaced my hubs with ABS I no longer had the issue