One problem related to wiring has been reported for the 2009 Kia Motor Optima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2009 Kia Motor Optima based on all problems reported for the 2009 Optima.
After a battery replacement, the battery sparked when the car first turned on, but the car immediately turned on. From that point forward we had the check engine light on, the brake light on and two other lights on the dash on constantly. We took it in and spent $4000+ on oil changes, front end replacement and several other items that took almost a month and a master mechanic from kia to find out that the problem was a wiring harness issue. We were told that we had been in an accident and that because of that it wasn't going to get replaced under warranty. The car was never in an accident, and the wiring harness still shows four lights on the dash. If a simple battery replacement can cause the wiring harness to fry there must be a problem, and I don't think it's the battery.