Security lights flashing after battery cable removal-no start

Dirty battery cable terminals, faulty cables or loose earth connection, engine wont turn water in cylinders, battery goes open circuit under load. can cause this fault.

well first thing to check is the battery working. turn the headlights on. do they light up bright. dim would me you need to charge it or replace it. if that's not the issue the starter will go and that makes the engine turn over when you use the key. the igniton or shifter could be another problem try starting it in neutral if you suspect the shifter cable. my guess is the battery. or the connection for the cables to the battery. but need to check and test stuff

the cable /fuse to alternator has nothing to do with the start and run function if the battery is charged up and in good condition ,sounds like the main battery cables have a bad contact/connection or battery is shot<follow battery cables and remove all points of connection in engine bay area clean contacts with sandpaper and resecure all connections 1 AT A TIME! to make sure none are swapped around by mistake ) on both earth cable/negative and the positive/power cables,make sure terminals on battery are clean and tight , try boosting/jump starting your battery with jumper cables connected from another cars battery positive to positive .........negative to negative and see if it starts ,i doubt the problem of starting up is the alternator unless battery is flat and not being charged by alternator ,by jump starting with another baterry will give you the answer once all baterry cables and connections are clean and secure

You've got a good start measuring the voltage at the battery. Looks like you've got a low voltage problem. Common on the GM side post batteries is battery acid leaking at the positive battery cable post on the battery. I would recommend removing and checking the cables/posts on the battery. If everything is clean, reassemble the battery cables to the battery. If there is excessive wetness or corrosion on EITHER of the cables/posts, you should replace the battery first, and clean the cables. A leaking battery is going to give you more trouble down the road if you just clean it. If the battery connections on the existing battery are clean, charge the battery with a battery charger, or jump start the car. Use your trusty meter and measure voltage at the battery with the engine running. (Also do this if you replace the battery for leaks). You should read in the neighborhood of 13.5 - 14.0 volts if your charging system is working correctly. If you are reading in the low 12 volt range with the engine running, something is wrong with your charging system, and most likely putting a strain on the battery, preventing it from receiving the charge it needs. If your existing battery is not leaking, cables are clean and tight, jump starts okay, reads 13.5-14ish volts with the engine running, but refuses to crank the engine over after the engine runs for about 15-20 minutes, it's time for a new battery.

SOunds like they might be tight or need cleaning. I always take a battery brush to yerminals whenever i remove them they should be shiny and silver inside to get good contact. they should not be able to be wiggled at all. if this does not solve the problem check your ground. the negative cable should go to the body or frame. find this and clean the connection and make sure its tight. This is all assuming you have a good charge on a good battery

I’m happy to help further over the phone at https://www.6ya.com/expert/paul_0efc97cca45309c1

Hello: Make sure the battery cables are clean No corrosion, and tight. If the security light is not flashing when you try to start it, the have a helper hold the ignition switch in the start position and you go under the car and hit the starter (not to hard) near the end that goes into the engine, If it starts then you need a starter. If the security light flashes while trying to start you have a pass key problem

It is your battery it is low or the battery terminals need cleaning disconnect the bettery cables and take a piece of sandpaper and sand the battery post until it is clean and do the same at the cable end and connect them back up if it still wont start jump it and then disconnect the positive battery cable if the engine dies when you disconnect the cable then you have a bad alternator

Possible poor battery cable or cable connection. Remove the cable terminals from the battery, always remove ground or negative first! Use a small brass brush to clean the terminals also clean the connections too. Next follow the ground cable, to where it mounts to the body or engine. Remove this connection and clean both surfaces of cable and mounting point; re-install with proper torque on bolt. Be certain to check the cables for any short bends, thses can cause the inner cable to break and have poor connections Look for a gronding strap that runs from the firewall to engine, insure its clean with good connections. Then check the connections at the alternator, be certain that these too are clean and tight. After which reconnect cables to battery positive first ground last. Recharge the battery if she works great, you found the problem. If you still have issues it would appear your battery has or is loosing a cell and may need replace. This can be checked at an autoparts store. Lastly may be issues with charging system, alternator?

I hope this may have assited you,
Tom

Sounds like a bad low tension connection. Check to make sure battery leads are clean and secure on battery. Check same at the starter motor and body earth. With this done, try starting ( with jump if necessary) . If still no joy, remove the starter motor, clean and or replace copper contacts in the solenoid .

The factory security light will remain on - this is a standard feature indicating the car is dead.
First, unplug the hazard fuze in the engine bay (this will reset the ecu and remove the flashing)

Next, replace the battery with a new one (or one with proper charge) - keep in mind a small battery will not do anything for these cars, the engines require a lot to push them over (it isnt a honda)
*Make sure to clean the positive and negative battery cables from acid

Then just start it up :)