Dash light security is on
 

The security light came on in the dash and it is really screwing up my ride.

2000 astro 4.3 in this case. The security lamp does not always come on but when it does bad things start to happen.
Headlights will go out while driving , the radio blinks, the door chime starts but very faintly, dome light don't function and the high beam light indicator will not work or will not go off when switched to low beams. This is while the engine is running.
This has 165 K on it and the engine is strong but since it failed E check and the garage serviced it it will not start cold without dumping starting fluid into it while it is cranking.
So now it takes two people to start the van.

Anyone have any ideas,
Thank you in advance

make sure you check all your battery post connections,if there is any sign of green corrosion on the battery post it can cause all kinds of issues.there are alot of issues with drivabilty problems due to bad battery and ground connections including power wires to the starter and engine grounds including body ground .a bad bcm body control module can also cause issues.is the engine check light on or does it come on when your security light comes on.when you say you have a starting issue when cold it could be low fuel pump pressure.easy way to check would be with a fuel pressure gauge.i know the 4.3 engines need to see a minimum 52 psi to run.it could also be a bad ecm temperature sensor.i had one on a chevy truck that wouldn,t start at -10 and the scan tool was reading 350 degrees.i pulled the plug to the ecm temp sensor and it went to -40 which is failsafe and the truck had started.there are many posibilities and if you can bring it to a good mechanic you can trust that might be the way to go.wiring issues sometimes are time consuming and costly .hope this helps.