04 Chevrolet Colorado blower motor

The blower switch itself.

Check main fuse for blower motor , I am almost certain that the main fuse power a purple colored wire that goes to the blower motor ....also check ground at motor.

This power supply I mentioned above is power for high only on the dial...hope this helps

I had to replace my switch as fan blower stopped working and then later on the blower only worked on high and yet again it was the Blower (high, medium, low, on/off) switch bad again.

Are you replacing it with a new switch each time?

This isn't the same problem as described in question. He says its working fine through the resistor block yet has no high which is live battery power and I assume it run through fusible link or fuse of some sort?

First time replaced new, second time replaced with used. May or may not be your issue just that for sure on one I know of the switch failed twice.

The back inside of my switch the first time was melted looking not sure about the second time.

I looked back at the whole picture and I am not seeing where the blower motor was replaced.....if it hasn't it definitely is a large possibility. Drawing to many amps cause switches and resistor packs to fry. Hope this helps.