New Burb, wont run, help?

[Branpowell]

Long story short, can't find the issue.
Bought a (really,really)unloved 99 gmc suburban k1500 270k to replace my old 2wd pickup.
Heard it run once when I bought it, for 5 minutes. Signed paperwork over, wont start back up.
Symptoms: 1. Dash Security light stays on all the time. 2. Starts for approx 2 seconds then dies. 3. Security light does not go out during 10 minute passlock learn procedure.
Possible symptoms, possible uncared for caritis: 1. headlights do not work(have not checked for voltage at lamps or switch) 2. Wipers acted crazy if turned on, don't wanna turn off. 3. CEL on when trying to relearn passlock, but only until engine started, then it goes off.(don't have scanner atm)
What I have tried so far to diagnose and replace: 1. Replaced fuel pump. 2. Replaced batteries. 3. Tested resistance on ignition passlock resistor(ylw to org/blk), open circuit. 4. Replace badly cut key copy that turned 1/5 of the time with gmc cut from vin key. 5. Wired in 1200k ohm resistor to bypass ignition passlock on ylw wire to org/blk and added ground leg to org/blk for fresh ground reference. 6. Checked passlock module for burns, heat, etc. Looked perfect. 7. Tried passlock relearn both 10 minute and 30 minute procedures,

I'm running out of things to try and I've been researching hours getting nowhere... any ideas at all???

 

[Branpowell]

Update: headlights and interior lights due to missing 50A lighting fuse under hood, replaced. All fuse checked and working, only fuses pulled are interiors air bag #10 10A and interior Illum #14 10A.(for battery saving while I troubleshoot and have steering wheel off to work on ignition)

Pulled 1200ohm resistor in passlock bypass to retest wiring. Yellow wire to ign cylinder to org/blk(uncut) reads open circuit, no resistance at all in all key positions. Yellow wire to wiring harness to org/blk(uncut) reads 6k ohms resistance. Org/blk to body ground reads 3k ohms resistance.
Security light still on steady, does not go off during passlock relearn procedure...
I have a obd2 scanner on the way, should be delivered tomorrow. Will pull codes at that time. No CEL at this time.

 

[Coveman]

I’ve had that security reset issue twice on my 99 burb. The reset procedure did work both times but you may need to run through it a couple of times for it to work. Im thinking i gave it 30 minutes last time. Also check your voltage, you may have a weak battery compounding things.

Its kind of a weird glitch, it sounds like its looking for the chip in the key to release the ignition hounds but my truck never had chipped keys in he first place.

 

[HotWheelsBurban]

It probably is the Passlock box, this sounds exactly like what my 99 Burb 5.7 vortec 2wd did repeatedly last summer. The truck had an aftermarket alarm system when I got it used, thought that was the problem. Had that removed, worked fine for a week, then back to the BS. Finally it got to where I would try to start it several times a day and it wouldn't stay running. Basically: cranks fine, starts, runs for 2 or 3 seconds, then shuts off. The relearn processes would work sometimes, then not. Then I did some research on this forum and found out about deleting the Passlock in the PCM. Found a tuner that could do it , paid them, no more issues. These boxes are like the radios, they rattle apart bouncing around in our trucks for 20 years and the soldered connections come loose. Can't always see them either. Good luck and let us know what finally fixed it