Hi tig57. Welcome to the forum. I would start by checking the charging system. In particular, use an inexpensive digital voltmeter to measure battery voltage with the engine off and with it running. Engine off you should find near 12.6 volts for a fully charged battery. If it is around 11 volts or less, suspect a defective battery.
With the engine running, you must find between 13.75 and 14.75 volts. If it is higher that 15 volts, suspect a defective diode inside the generator. The voltage regulator will see the dropouts and try to raise system voltage in response. Computer modules, which includes the instrument cluster, don't like wrong voltages and voltage spikes.
Even if the battery voltage is normal with the engine running, there could be excessive ripple that the voltmeter won't pick up because it can't respond fast enough. A shop with a charging system tester that measures ripple will be able to identify that. You can also disconnect the generator temporarily while the engine is running. If it is the cause of the problem, the instrument cluster should behave properly when you do that.
caradiodoc
Aug 23, 2010 at 7:13 AM
