my sister has a 06 trailblazer and the blower motor started acting up and it only worked on high when it wanted too. now it kicks on hardly ever and it seems to work as she is going down the highway. I am sure that has nothing to do with it. but she also said it barley blows out when it is on. is this the resistor or the blower motor itself? i looked for the blower motor on the fire wall and it wasnt there lol so im guessing all of this is tucked underneath the dash any knowledge and tips would be great thanks

 

Probably the resistor, both the resistor and motor can be found under the passenger side of the dash. 99.9% of the time with most newer GMs when the blower motor resistor fails it causes the connector for it to melt so check that over pretty good, the connector pigtail from GM costs more then the resistor does unfortunately. Iirc they aren't too bad to get to on the TrailBlazers.

 

Resisters can fail just like light bulbs, but a blower motor going out can also cause excessive load for the resister causing it to burn up. Most of the time a resister fails it takes out the lower speeds leaving only high. If all speeds are out now, makes me wonder if it needs both.

 

WARNING it is not just the resistors, this is a bad problem with the GM's. The blower motor is drawing too many amps and has burned the resistors, and the connector to them also, I garuntee it, you Will need a new motor, resistors, and a pigtail.