1996 chevy blazer dome light and alternator problem please read and help

[lifteds10man]

ok i got 2 very mind boggling problems with my 96 s10 blazer 4 door if i hit the power locks to lock my doors the dome light comes on but if i hit the power door locks to turn them off it turns the dome light off too and the second problem is when i start the blazer the alternator is wining and not working but when i put it in gear it is 100% fine im puzzled can any help me out here

[chrisb123]

Hi,
Did your check your dome overide button on the dash? Altenator whining could be bad bearing or some other pully, Check voltage or take it to autozone to check it for free.

[lifteds10man]

mine dont have the override button on and its wierd with the alternator it checks out fine i work at advance lol but when i first start it the alternator whines and there is no voltage from it then when i put it in gear it stops whining and is fine even when i put it park it stops and with the dome light its wierd too if the power locks are hit to lock the doors the dome light comes on sometimes the whole time sometimes just for a second or 2 but if it stays on and i hit unlock on the power door locks the light goes out works fine with the door open and closing but the wierd thingwith the power door locks even if i it the lock button on my fob it does it but i can lock them manually and it wont come on

[chrisb123]

If you have no voltage at any time then I would suspect a dying alternator. When the vehicle runs just on battery votage for any time it can cause havoc with the electrical sytem. A faulty ground wire connection can also cause problems. If you have a aftermarket audio that draws a lot of amps without proper wiring and componets IE Capacitor that can kill a alternator. Since you work at a place to get replacement parts try out a good quality replacement. Check all wires for proper connection and corrosion especially ground wires. These vehicles are known for ground issues. Check all fuses. Check your belt and tensioner. The alternator spins 2-3 times faster then other componets a loose belt or bad tensioner could be slipping. If you have access to the wiring diagram isolate the lighting and check where the ground connection is. Let me know how it goes.