I've got a 2005 Blazer I picked up cheap which is a non runner. Story from the previous owner, who seemed fairly trustworthy (Helped me load on the trailer, countered my $800 offer with $600 if I brought my own tires and then swapped the tires for me), was that he lost the key on a hike, had the vehicle towed home, replaced the key with one from the junkyard, still didn't start, proceeded to rip out a command start system and patch the ignition switch up, still no start. I then purchased it from him in that state. Vehicle had every indication it was previously being used and was planned to be used as a daily (new radio, new winter tires, it sounds strong while cranking, etc.). He had attempted to follow the wiring to no success and was over it, now it's my problem. I believe when he swapped the key the PASSLOCK system probably locked him out and then that led him to rip out the command start.

The starter tests fine when jumping the relay, I have spark as it will start on starting fluid. I have tested all fuses ECM and IGN related and they have power. I replaced the hacked up ignition switch and verified that I have 12v on the yellow crank wire when the key is on CRANK and 12v on the Pink, Orange, and White wires in RUN. I have disabled the security system on the vehicle via Tune, the light does not illuminate (It has the same settings as my 1997 Blazer which runs a 2005 ECU as 1997 had no security). When applying 12v to the priming terminal on the fuse block I can hear the pump click but not run.

I've hit a wall at this point and its starting to get quite cold up here to be tinkering outside for hours. Any ideas on what to test next? The next break in the weather I get I will be crawling underneath and testing the P/N switch - I believe it should have 12v on the purple wire in either Park or Neutral? Please correct me if I'm wrong. Besides that I have no idea and might end up moving on from it if I can't make any progress. If the fuel pump is bad I have no issue replacing it but the No Crank and No Fuel are either connected or isolated. If they are isolated I'd like to at least get the key to turn it over before doing the pump and if they're connected then I'm hunting down one issue which I doubt that a failed pump would cause no crank at the key.

The command start installed was an Autostart AS-1725, I still have it in the back of the vehicle. The installation diagram shows little interaction with anything besides the ignition switch wiring. As I'm typing this I see in the manual it has a starter wire output with a 30A fuse, that should be connected to the starter wire so I will check that along with the P/N switch next.

Does anyone else have any ideas on what could be going on?

 

The highs and lows of repair got me good. I was able to fix it today. I did some digging around and found that the remote start was acting as a middle man for the fuel pump and crank signal. Patched the wires together and it started right up!

 

Congrats!

And thanks for the follow up. These can really be helpful to others.