I have this 1988 mazda b2200 and when i got it figured out it had a dead battery so i go put a charger on it. I go out after a while and try to start it and while the ignition is on (not turning over) it makes this weird humming noise that appears to come from the disty. It sounds almost like being around a transformer and it just started happening today. ive tried charging the battery for a couple hours and it appears it simply is not going to hold a charge. Could it have been possible i damaged something with the charger on it? All the lights and everything work and the starter will click but it will not turn over and makes a weird humming noise when its on.

Beside the Body Config (Single Cab, Kin Cab, or Double Cab) and the 2WD or 4WD options, there are two different Mazda B2200 on our Local Market: One came with Diesel engine and the other came with Gasoline engine.

So, if it is Diesel, it could be some Damage on the Glow Plugs Control unit...

if it is Gasoline, it could be a Worn Relay making false contact, or a Solenoid at the Starter...

Kind Regards.