Hi Scotty, I have a Kia Optima 2000 model, most times if I start the engine, my AC automatically…

Hi Scotty, I have a Kia Optima 2000 model, most times if I start the engine, my AC automatically picks and it resets to 25C but i put it off at 17C before turning off the engine.In some cases, while trying to start up the engine, it drains the battery an makes it difficult to start. In this case, I would need another battery to start the car. After watching your training video, I have tested my Alternator if it doesn't charge the battery but my charging system is fine from my multimeter readings (i.e initial battery readings 12.8Vdc, with engine start up 14.0Vdc, then all electronics put on 13.5Vdc, voltage drop test on both terminals of battery and alternator are fine.
Any day it wants to start this drama, even without starting the engine, just at the open of the ignition, the AC picks up....and resets back to 25C. After a period of time it comes back to normal and friendly for about another 3-4 days....The most annoying thing is that it stops on the road while driving... This is not a fuel injection system problem because as soon as I get another battery, it starts at one turn of the key and runs like crazy until another visiting day.

So if the battery has been replaced, then it kind of sounds like the charging system isn't working like it's suppose or you have a very bad parasitic draw draining the battery after you shut the car off. Another possibility is there's a wiring connection issue at the battery, issue with wiring to the fusebox, and/or bad ground to the frame. Just be sure the battery terminals are shiny clean and tight.

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