2012 Cascadia ISX Cummins. Vin BJ1508. Cab 33 code comes up on the display on dash. AC has quit working since. I have read that this is a SAM cab code. Had it to a Cummins shop and he says it is a Freightliner thing. Any suggestions?
Have you checked the fuses? On the ProStar, and I know you have a Freightliner, but there is a 30 amp fuse, or breaker that likes to fail that powers the blower motor. I would not be surprised if it is the same in a Freightliner. Something to check. If there is a breaker, push in type, replace with a standard fuse and give that a shot. Do the same for all AC related fuses in the fuse block. And do not trust that the fuse or breaker is doing it's job. I have pulled perfectly good looking fuses and breakers and replaced with new, and suddenly everything is working. They look good, but are actually not.
I discovered this after getting ripped for $600 at an International dealer. It was not the parts, it was the .10 fuse. Still pissed about that one!
Have to take glove box out to get to fuses. No biggy. I did check em but i'll do it again. Also checked fuses under hood by the steering column. Will do that again as well. I feel your pain on the dealership. I was at a Freightliner for 5 hrs last week to run a diagnostic to read codes and to replace a fuse. $157.00.
I get that code often; same vehicle. My A/C goes out while spending time of city streets, but comes back after 5 or 10 minutes on the road. I'm guessing a pressure switch in the A/C system or the evaporator is freezing. I don't get much time at home but I'll eventually find the culprits.
Good Luck!
Also check your fuses in the PNBD it is located under the hood, looks like a fuse box on the firewall near the steering shaft.