03 Trailblazer blowing out of vents off and on
I got in it this morning (around 8:00a.m.) and
the heat and a/c wouldn’t blow, on my way
home from work it just started working again.
Does anyone know what could cause this or if
it’s a common problem?
No I didn’t get the battery replaced I heard
about people having that problem but this
was out of nowhere
Most likely it's the resistor block near the blower motor. GMs from this era were plagued with resistor block burnouts. Hope that helps! Jim
note the diagram for blower motor, manual temp control. When problem is ongoing check voltage and ground at blower motor. Purple wire is voltage, black wire is ground. If good voltage and ground, suspect the blower motor. the brushes in blower motor, where applicable, can get worn down, the blower motor may run intermittently. Just a thought. You can use a test light to check voltage and ground.
Blower motor resistor. Make sure you replace the pigtails to it also, they melt on the inside. Also, note whether you have automatic climate controls (digital) or manual. Digital is called blower motor control module, manual is called blower motor resistor. Both look the same, but are not interchangeable.
