99 Chevy Blazer loosing power while driving

Check the fuss we and groung

Look underneath you battery box and you will find some connections that go bad. Yea, ya gotta remove the battery and box.
Lee

bad switch or motor
To check the motor the motor has two connections. One for up and one for down. Try hot wiring the connections to check. If it works the drivers switch is bad

Sorry ,there is no easy way to do this ,just take your time with this job,and you will only do it once.

LET ME TRANSLATE

You may have vapour lock in your heater lines. Start engine, put heat lever on high, disconnect one of the lines on your heater core, the one on the flow out side, & see if you have any air coming out. Once antifreese comes out stick line back on & retighten clamp. Make sure your cooling system is topped off. Also your water pump may not be functionihg to it's maximum. Take rad cap off cold & view flow rate. If inadequate you may have to replace the water pump. Good luck!

Light switch assembly, I would start there. They do fail, and can fail like yours has.

check the tranny fluid level, then make sure the parking brake shoes are not rusted in place, if its a auto trans the coverter has drained all the fluid,

it sounds like your alternator quit charging and then your battery died. do you have a battery charger? if so, charge the battery and try to start it. If it starts but the charging light is on, you likely need an alternator. Most auto parts stores can test it for you.

Well odds are that your blazer is fixed by now. Either way sounds like a bad battery, that's why you need jumps all the time. Why it would die, there are too many possibilties off hand. So what was wrong with it?