2000 Blazer LS 2 door nightmare..
 

My 2000 Blazer had some issues before. Ha to put new instrument cluster and light switch and of course the back tail gate lock prob. Pain but done, ok. So a couple weeks ago I come out of dentist office after about an hour there and go to start the Blazer I get click click click. Dead battery. What? Open the hood and there is power steering fluid in front sprayed and I hear a buzzing sound. Ended up having it towed home still buzzing. Start to work on it ok leak in ps line no problem. The fuel pump had killed the battery completely. Pull the relay it the fuel pump stops. Then the dome, running, lights aren't working but head lights are ok. Goes into passlock since the battery was dead. Charged it and the light comes on not blinking. Try the relearn and the security light never goes out. Start for the typical 2 sec and won't keep running. I can't find anything so I put a 2.2k resistor in between the yellow and black /orange wires. Those 2 wires I cut off from the switch and connected with the resistor. Go to relearn and wants to start and security light is on once again not blinking and never goes out fro relearn. Usually when I connect and reconnect the battery. I can also always hear the lock mechanism for the tailgate go on but nothing now. I'm at a loss other than an exorcism. Any ideas? Thinking maybe ignition switch but I don't know. It doesn't have a chipped key for security. Thanks.

UPDATE: So I wired the resistor in wrong. Ok. I fixed it no biggy. Tried to start and relearn and security light still doesn't go out. So I left it set for a couple hours and decided to remove the neg side from the battery for the night.I start loosening the terminal bolt and about half loose the car turns over and catched for the 2 sec again. Took terminal off the rest of the way and then put it up against the battery and it tries to start again. Scared the crapola out of me. Key wasn't in the ignition and it was turned off. Went back later and tried again after the battery was disconnected for an hour and nothing happened I did notice nothing, no clicking or anything, just total dead. Weird or what? Any ideas appreciated.

I would lean toward a bad ignition switch or possibly a PCM issue.
Any salvage yards nearby that you could get a used ignition switch cheap just to try?

So I left it set for a couple hours and decided to remove the neg side from the battery for the night.I start loosening the terminal bolt and about half loose the car turns over and catched for the 2 sec again. Took terminal off the rest of the way and then put it up against the battery and it tries to start again. Scared the crapola out of me. Key wasn't in the ignition and it was turned off. Went back later and tried again after the battery was disconnected for an hour and nothing happened I did notice nothing, no clicking or anything, just total dead. Weird or what? Any ideas appreciated.[/QUOTE]

By arcing the battery terminal you surged the computer causing the remote start to activate - been there done that - I know that you was removing the neg lead but surging the electrical system usually only happens with removing the pos first or hooking the pos up last - hence the reason for removing the neg first and reattaching it last

https://cimg7.ibsrv.net/gimg/blazerf...60fa6d9376.jpg
https://cimg8.ibsrv.net/gimg/blazerf...128707e115.jpg
So I found this remote mess wrapped up like softball under the lower driver cover. I cut it out and got an ignition switch from the boneyard. So I end up at this point with the lights in pic never going off even with the key out and off. No start of course. Security light never goes out and doesn't blink, The driver side door lock actuator isn't working but passenger side is., dome and running lights still don't work, (replaced the switch already), the push button top map lights don't work, and the rear hatch button doesn't activate the latch actuator. This things didn't work before I pulled out the remote set up. I sure hate this vehicle right now! Any other ideas? BTW: If I would change the bcm, I've read that it will need flashed but if I use the Ecm that matches it from same vehicle would it work without flashing anything? That is finding a vehicle that matches as close to what I have now.

So that is why we are supposed to diconnect the negative first. I always prefer to know why I need to do something a certain way. Nice. :)

It was from removing the neg first. I'm at a loss of what to do or check next..

There was a previous post about similar issues. it turned out to be the wiring harness under the carpet on the floor board in front of the drivers seat. That main harness is also next to the speedometer cable rubber plug that could have leaked water in the cab over time and is shorting out or disintegrating the wire protective sheathings. May be worth a check.

I think I saw that. I'm going to take a look. Waiting for a service manual to come with wiring diagrams to see what connects to what.

Think of it in terms of water, { bubbling brook verses a dam breaking} when the positive is hooked up first the voltage pre load's the system and when the neg is hooked it's a small voltage trickle thu out the elect system as it's pre loaded with positive voltage.{bubbling brook}
By hooking the Neg up first there isn't a pre load and the voltage is a sudden surge wave to the Neg. {dam breaking} And by removing the positive first there is muiltble waves of voltage with breaks of none in-between being sent as it arks until it's all the way removed.