The buzzing indicates the battery is run down, as you mentioned, or there's a bad connection in one of the battery cables. If you removed parts to have them tested on a bench, that is the least effective way to do it as it removes all the rest of the circuitry from the tests. Start by measuring the battery's voltage. If you need it, here's a link to an article on how to use a digital voltmeter:
https://www.2carpros.com/articles/how-to-use-a-voltmeter
They're using an "auto-ranging" meter here. That's an expensive feature you don't need. Harbor Freight Tools has a dandy meter for around $7.00. Also look at Walmart or any hardware store. I can help you set it up if necessary.
A good, fully-charged battery will read 12.6 volts. If you find it's closer to 12.2 volts, it's good, but fully discharged. Charge it at a slow rate for a couple of hours with a small portable charger, then retest it. If that gets the engine started, we'll need to continue with charging system tests. You'll need the voltmeter for that.
If the battery's voltage is down around 11.0 volts or less, it has a shorted cell and must be replaced..
Let me know what you find up to this point.
SPONSORED LINKS
Wednesday, March 29th, 2023 AT 4:43 PM