This is an intermittent problem, so any testing has to be done while the problem is occurring, otherwise everything is going to test okay.
This type of problem is usually caused by a failing generator, and this type of failure is most commonly attributed to worn internal brushes that are making intermittent contact. This can be expected at the mileage you listed.
The warning light can be misleading. It's not related to the condition of the battery. It means the charging system is not keeping the battery charged while you're driving, and that involves the generator and its built-in voltage regulator. In your application, the voltage regulator turns the "Battery" warning light on during a no-charge condition, like on all other cars, but also for an under-charge or an over-charge condition. Voltage regulators can fail in multiple ways. One way results in system voltage going too high. That might explain the bulbs flickering and burning out.
Corroded connector terminals can cause all the same intermittent symptoms as a failing generator. Check for corrosion or spread terminals in the connector at the rear / side of the generator. If you follow that wire harness, there is usually another two-wire connector about 10 to 15 inches from the generator. Check those terminals too.
While you're under the hood, follow the smaller battery positive wire to the under-hood fuse box and be sure that connection is clean and tight. That is a real common source of trouble on all car brands. When using metal tools on that connection, don't let them make contact with any metal part of the car at the same time. Doing so will result in huge sparks. Follow the smaller negative battery wire to where it bolts to the body sheet metal and be sure that connection is tight and not rusty.
Wednesday, November 25th, 2020 AT 9:04 AM