GMC Repair: electrical, gmc savana, alternator wiring

Question
I changed the alternator on my 1996 GMC Savana two days ago. This morning I was driving with the headlights and radio on and everything was fine. When I turned the heater on, the battery gauge started twitching constantly and the headlights dimmed with each twitch. When I turned the fan to low, the flickering stopped. I tried a couple more times, and I had to shut something off to stop the gauge from twitching each time. What would cause this?

Answer
Just because the alternator is NEW or REBUILT does NOT guarantee that it cannot be faulty. Take it OFF the vehicle and have it tested.

Other possibilities are an internal battery problem of which you should also have the battery tested, a corroded battery cable(s) and or cable ends. Loose electrical connections at the alternator wiring.

Check and clean all the wires that are connected to the battery cables for looseness and or corrosion.

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