Ok so I shut my truck off with the heat on. Come back and it isn't working. When you change the **** from 4-5 it makes a click noise. That's the only noise you get. Fan does not come on at all. Nothing blows out the vents or makes any noise.if I leave circulate off it will blow hot air and if I use the temperature adjustment it will change to cool etc but not with circulate on and none of the 5 speeds work....is it the resistor? Or the actual motor? Its a 05 sierra.

 

Damn, your explanation is making it hard to follow the problem. As I understand it the blower only comes on in fresh air mode with heat on.

Can you confirm the fan is actually blowing and not just allowing outside air to pass through? Do all 5 speeds work in fresh air heat? Is your a/c the auto climate contol type?

Post up the last 8 of your VIN for me.

 

No the fan does not work on any of the five settings and does not blow at all. Moving from 4 to 5 on the **** it makes a click noise like a relay or circuit coming on but nothing happens. It has the manual ac controls. It only lets outside air in but if you do change the temperature settings it does get hot or cold but non of the fan settings work on not circulate also.


I'll post the vin in alittle while. I'm not with the truck right now. When I get home I'll post it. It's a 05 base model work truck.

 

Thanks for clarifying. I expect it to be either the resistor or a connector on one end. There has been a number of design changes, service bulletins and warranty extensions associated to all of them but it would be wise to at least continue narrowing the cause.

Next step is to pull the connector off the blower motor and the resistor and look for burned terminals. To rull out the blower motor you could jump voltage directly to it and when it start spinning you'll know the failure is somewhere upstream.

 

I got it working. Took the connectors out. Cleaned them up. Checked the fan and it works. Scrubbed it all up and put it back together and it works fine again.

 

Mine started acting up so i replaced the resistor... started acting up again and when checked it the connector was melted.
new pigtail and resistor fixed it all.

 

Good to know. When I get a chance I'll go ahead and replace those.

 

Look for burned terminals david. The problem will return if they are scorched and it would be terrible if it started a fire in your truck.

 

They did not look burned to me. They all looked identical sliver to imo. All very similar. I'll check it again soon and watch it or just go ahead and replace the pigtail and resistor.