Have a 2000 chevy blazer, just replaced blower module .still no heat or ac and selector switches don't light up when pressed

First test the blower motor by jumping 12 volts to the motor connector. If the blower runs pull the dash switch and check for a burnt connector and overheated wiring at the blower speed control switch, if that is the problem, replace the switch and the wiring harness to the blower motor. I think there was possibly a Recall or Technical Service letter on this problem.

Looks like you are not alone in this. Take a look at this video that may help solve your issues. Good luck DIY How to Replace Heater AC Blower Motor on Chevy Blazer GMC Jimmy S10...

blower motor needs to be replaced. tap on blower with rubber hammer of hand key on, fan switch on. you will see fan start to operate..

that is strange. for the ABS has its own relay and so does the heater blower motor. they do not share the same outlet , I would check the wire at the bottom of the fuse box

First check the 15 amp HVAC fuse located in the main fuse block inside the car on the passenger side of the center console, under a cover. If the fuse is good, then the problem may either be the HVAC blower switch (which is the fan blower selector switch), the fan blower motor resistor, or the fan blower motor. An auto repair manual will explain and illustrate for you the steps on how to check each of these components.

Even after pushing the ac light switch on, the fan blower selector switch has to be turned on as well (working) because it provides an electrical path to the positive side of the battery to complete the circuit and turn the ac light on. What the ac light switch does is provide the electrical path for the ac compressor clutch to come on through the ac control relay which is controlled by the car's PCM(computer) when you want ac, but the ac light switch still needs to run through the fan blower selector switch to receive its power. You can turn on the fan without the ac light switch because it gets its ground path(negative) from the blower motor. So the blower motor has to work in order to provide a ground path for the fan blower selector switch to be functional. You could have a faulty blower motor which is why no air blows through the vents. The fan blower motor is located inside the car on the passenger side underneath the dash at the bottom end of the glove compartment box. You'll see it. It's right above where a person rests their feet on the floor. Therefore, if your 15 amp HVAC fuse is good, check to see if you have voltage at the blower motor connector. Unclip the connector and with the ignition on and the fan blower switch moved to any one of the first 3 selections, check for voltage using a multimeter. The voltage will vary because there is a blower motor resistor. Voltage should be higher on setting 3 than 1. If you do have voltage at the blower motor connector, check for a faulty blower motor. The auto repair manual will tell you how to do it using jumper wires.

It's normal that your car is running hot because the radiator fan works in conjunction with your ac compressor. If the ac is on, the radiator fan will be on and therefore the engine coolant temperature will stay in it's normal operating range. If the ac is off, the radiator fan will stay off as well and the engine coolant temperature gauge will begin to rise and show pretty hot (especially at idle). It will do this up until a certain degree then the radiator fan should turn on thermostatically and stabilize the temperature. It's scary and I know what your saying because it does that to my car if my ac isn't on. Don't worry it won't overheat.

check your blower hoses to see if one or more have come loose or got redirected or the selector switch isn't functioning properly (is it blowing better on defrost as opposed to floor vents, or forward vents, etc.)
Good luck

Check on and off switch it may be defective.

yes the heater controls are vacum however the blower motor is not. a new control panel is an option and may fix it. if it was my blazer i would first check the fuse boxes onder the hood and in the side of the dash driver side. if they are good i would go to the nearest auto parts store and buy a test light. this will aid you in making sure what the problem is before you go spending money on replacement parts. the blower motor is in one of two places. its most likely under the dash on the passenger side. there is a cover that you will have to remove directly under the glove box. once removed you should see a large red and a large black wire. these are the power and ground for the blower motor . in some gm's these wires go into a resistor. the harness plugs into the resistor and the blower motor wires come out of it. ok now that we are a little bit familiar with our suroundings the red wire i told you about is the hot wire if you ground the clamp on the test light to the door hindge. (make sure its a good ground by touching the positive batter terminal. if the test light lights its a good ground )now unplug the blower motor and touch the metal posts in the end of the plug that belong to the red wire. if it lights when the key is on and the blower control is on in all posisions you need a blower motor. if it does not then you need a blower motor resistor.

the problem is not the selector, it is the air temp control blend door motor, the only way to fix this is to remove the dash, there is no way to manually close the door for heat because you can not reach it.

These trucks have a problem where moisture builds up in the heater box then freezes. When this freezes and you change your heater settings it breaks the shaft for the blend door. If this is what happened you should be able to look under the dash above and to the right of the gas pedal and you will see two vaccuum accuators one of them you should be able to wiggle around the linkage if it is broke. To fix this you need to remove the entire dash to get the heater box out which involves discharging the AC and draining the coolant because the heater core and evaporator come out. Please rate.