2007 chevy trailblazer remote start issue

Thanks the reply, I'm going to try and touch on some of the points you mention... 1- When it works, the dash lights all come on, you can hear the fuel pump run and then 2-3 seconds later it will crank. When it doesn't work, the lights come on, but no fuel pump. The remote start seems to go through its 3 attempts, but with no crank. I have sat in the truck and tried to remote start it with the fan on high, then after the first attempt, turned the fan off, the truck started on the 2nd attempt. 2- The wipers and radio do work when the remote start starts the truck. 3- I'm thinking that the harness you mention is the one with the white label "fap fap fap" on it. 4- replacing the ignition switch was an attempt to shut off the dimly lit battery light in the cluster, no so much for the remote start.(But would have been a bonus if it fixed the RS too, lol) 5- the only thing I'm not sure of is the tach connection. Because I didn't want to mess with their install (untape and see what is connected where) and void any install warranty, but at this point, they want to remove the system and refund the money, so there is no concern on my end about the warranty. I feel I need to state that I'm not unhappy with the shop, they have tried to fix it 4 times now. Being from the trade, I know that you can't afford to spend huge amounts of time on a car, and the remove and refund is the best way for them to get away from it. However, this still leaves me with no remote start. That is why I'm trying to problem solve it myself. I talked to Directed Tech Support today and they suggested taking it to another dealer to see if a fresh set of eyes could help. Thanks again for the replies, I'm not a huge contributor to this forum, I contribute on other, more repair based forums. It is nice to know that there are people willing to take time out when they can to reply. Hey, is this supposed to spark like that?

Try turning engine checking off or go to voltage just for grins since u can't over crank, since you mentioned it doesn't start that's leads me to believe its a pass lock issue or the physical unit itself

See if it's wired d2d, the base model DEI stuff has issues with d2d and w2w is always the best option on them. drop the dash and see what the bypass led is doing when the vehicle dosen't start. Did they use a relay to trigger the 2nd accessory and 2nd ignition wires or just jump the wires together? What bypass was even used? Might be worth resetting and reprogramming the module as well.

Thanks again for the replies. It'll have to wait a few more days. It is currently -22C outside and we're expecting 15cm of snow tomorrow. (I do snow removal) Hey, is this supposed to spark like that?