Remote Start starts then shuts down
I have a 2004 2wd 3.0L. The previous owner installed a remote start system that worked fine when I bought the truck. About a year ago, the PATS system had to be reset and the dealership programed my two keys, but not the remote start system, so I had no remote start for a while. I'm not sure what brand of system it is, but there's an Xpresskit XK04 PATS bypass module installed that I can see.
Last week I looked up how to program the remote start into the PATS system and successfully did so, but now the remote start will crank, and it sounds like the engine starts, but it cuts out after about 1 second. The truck starts just fine when using the keys. I'm assuming a connection with the remote start must have gone bad over the last year of non-use, but I don't have any experience with these systems.
I'd rather not take it in the the dealership to get it checked, as I just spent a lot of time and $$ there having engine problems fixed. Any ideas on what to check for the remote start? I have a multimeter and know how to solder wires, so I feel like I can fix the bad connection if I can find it.