Do you have an in-dash voltmeter? Since I installed one into oth my 1986 244 and 1988 244 I can see what the alternator is "up to" easily.

Generally the job of the battery is to start the engine, period. The job of the alternator is to (1) recharge the battery after a start, and (2) run everything else.

So if you are seeing a dimming of lights, I would suspect the alternator.

Quick test. Check voltage across the battery terminals. With the engine stopped, you should see at least 12.0 volts. Less = weak battery. Check the water level, fill to mark with distilled water if necessary.

With the engine running you should get 14.0 to 14.5 volts. Less = weak alternator.

First thing to do on a weak alternator is to change out the brushes/regulator unit. Job can be done in situ, easier if the oil filter is out so combine job with an oil change.

Good Luck,

Bob

:>)


PS: At Wal-Mart, compare the Cold Cranking Amps (CCA) of the two batteries.