2004 Blazer LS 4.3 4WD. A few weeks ago the factory alarm went off for no reason. Checked, found nothing ajar. I used the Blazer a few days later and the ABS light came on for a few seconds and then went off. The seat belt light would stay on even though the belts were buckled. Fast forward to day before yesterday. Just before I went to bed I looked out and the headlights, tail lights and interior lights were all on. I used the remote to unlock the door and when I relocked it the lights went off. The next day the battery was dead. I changed batteries to a spare I had on hand. When I connected it there was a clicking noise from the area of the ABS module. When I turned the key on I have no dash lights, no gauges, no interior lights, no lights on the radio. When I turned the key to start, it cranks and fires up for about 1 second. All fuses under the hood and interior check OK. Open to any and all suggestions.

 

The wiring harness from the under hood fuse block runs under the ABS motor bracket. Mine was corroded, burnt and shorted against the firewall side of that bracket. It's not easy to get to or see, but it's worth checking. Especially since that's where your clicking noise is coming from.

 

Will check. Thanks. Clicking only happened when battery was reconnected the first time. Has not happened since. Other problems remain.

 

Installed new ignition switch and dash now lights up. Gauges (except fuel) now work. Security light stays on and still have the start and run for a second and stop. Battery will drain down overnight. Passlock problem ?

 

A parasitic draw test will show you which circuit is draining your battery. You tube has instruction videos if you've never done one. If fixing the problem circuit doesn't solve all the issues. It will cross one thing off the list.

 

Today battery was OK. Checked voltage. Security light still on steady. Speedometer is showing 100 mph. This is all new to me, so bear with me.

 

More tests today. Cleaned every ground cable I could find. Did a parasitic draw test. Used a DVOM meter. One lead connected to the negative battery terminal, the other to the disconnected ground cable. 0.01 was the result. Security light still on steady. Connected a Innova code reader and it said unable to connect.

 

Security light still on steady. Has never blinked on and off. Have tried all bypass remedies on youtube . Still starts and immediately stops. Since wife has taken ill, I have little time to screw around with it. I have decided to just scrap the thing and eliminate the frustration.

 

Wife is better so still trying to fix problem. What is the difference having the security on steady and flashing ? What triggers the steady light as opposed to the flashing one ?

 

Problem started with a unknown water leak. It shorted out a plug in the channel that carries wiring under the drivers side carpet. Had the plug removed and burned wires trimmed and capped (I think the plug was for a power seat which I don't have). It now starts and runs fine. All gauges work. Only problem is the air bag light stays on. Removed fuse until I find out why. Question now is what is under the black plastic cover on the transmission hump ? The water leak is coming from there. No garage and it's getting too cold for me to work outside (67 and the old bones ache from the cold).