My friend has been having some issues with his 03 WRX. When he lets the car sit for several hours, it becomes difficult to start, as if the battery was dead. Unfortunately, I have not been able to test the battery when it wont start, so I am not 100% sure if it is actually dead. I know for sure that the charging system works fine. Once started, the battery takes a charge, and after a while of highway driving it shows 100% on my charger. I suspect that we either have a short in the wiring harness, or the battery needs to be replaced.
Some back story:
The car had a coolant hose rupture about a month ago, and in his attempt to use the fans to cool the car off without the engine running (after being stranded on the road), he killed the battery. This happened twice in his attempt to get home. After I fixed it, he didn't have any problems with the battery. A few weeks later, he decided to purchase an alarm system for the car with the intent for the 2 of us to install it. We disconnected the stock security system, and got familiar with the wiring. We didn't have time to complete the installation that day, so we didn't splice into any wiring or make any connections whatsoever. I mounted the brain behind the cluster, and put everything back together. He went a couple of weeks with no problems, and now we find ourselves here.
The car is 100% stock, except for an aftermarket head unit (wiring checks out ok), and a set of component speakers. (aftermarket security system was never spliced into the wiring harness)
He is going to be replacing the battery with an optima red top, but I am cautious to do this now, as I would hate to see him burn through an expensive battery if there is a short somewhere.
What I have done:
-reconnected the stock security system
-charged the battery with my battery charger (to 12.9vdc, and shows 100% on the capacity)
If anyone has any ideas or suggestions, I would appreciate it.