If car starts with key but only shuts off when fuse is removed, what would this indicate is wrong?

If a problem occurs with the SecuriLock system, the indicator will flash
rapidly or glow steadily when the ignition is in the 3 (RUN) position.
just look at the lamp carefully.

all you need to do is see this, error and you know why IMMO cuts spark and engine will not start, BY DESIGN
check all fuses
scan the PCM see why IMMO fails
you said
chip key replacement<<< what does that mean, a lock smith or online hacker made, or what.? hacks do not work.
or mobile lock smith did this?
does engine crank or not. if yes and IMMO blinks wrong ,IMMO is not happy.
with key on LOCK pos. this lamps blinks to warn thieves, PROTECTED so find car with keys left in the car, not yours.

removing the 1n diode is wrong fault find the fuse to relay that is the cure

When you turn the ignition switch to ON(II), the immobilizer system indicator should come on for a few seconds, then go out. If the indicator starts to blink, it means the system does not recognize the coding of the key. Turn the ignition switch to LOCK(0), remove the key, reinsert it, and turn the switch to ON(II) again.If the system repeatedly does not recognize the coding of your key will need a repair.

fuel pump, fuses, and security. Start with fuses. Security light on. Lock the car down, all hoods shut. Open the door with the key. it should start. If you have an aftermarket alarm system, tear it out. Fix wires as you go. Check fuel pressure.

ignition switch is bad it sounds like. you have to pull steering wheelthere is usaully a switch inside you need to push in while you turnkey to pull cylender out

It wold be the faulty SAM according to my knowledge your technician have told you what's wrong in it. must check the front SAM and rear SAM as well,

is there a chip in your ignition key if there is you will need to have the key programmed and coded to your car this is a security feature that gm uses on most models newer than 1996

Check the fuse box. There should be something that tells what amp fuse #22 is. You may have a spare fuse in the box. Worse case scenario, pull a fuse of the same power from something that you don't need and use it til you get the key out. If the fuse keeps giving problems that indicates you need to get something checked out. DO NOT put in a larger amp fuse to get by. Fuses are there for a reason. It is not worth burning a Trailblazer up because of a $3.00 fuse.

It is indicating a problem with the engine & once the light comes on, it will prevent the engine from starting and will only go away after the problem has been rectified. Check the engine oil level, quantity of coolant, all the plugs and if you still cant find out whats wrong, then the best thing to do is take to a service center which has a computer for analyzing the error indicate what is the exact nature of the problem. If engine is OK then it will indicate what is wrong with the sensor which triggered this alarm & reset/calibrate it necessary...............sodeep

Faulty ignition switch. Replace