The heater shut off and won't turn back on. I checked the fuses and they are good and I checked the blower fan and it works too so I'm out of ideas on what to check.

according to the service manual there is no separate fuse for blower. If blower does not work at all check a/c fuse if good it could be the fan motor has built in resistor and can easily be bad I hope this helped and not made things worse Mike L.

check the blower relay sounds like sticking contacts

Test the electrical circuits ! Manual HVAC or automatic HVAC ?
Do you know the difference ? Heater / A/C blower motor electrical control diffrent . Manual has resistors an a relay for different speeds , automatic has a blower motor control module .Free wiring diagrams here http://www.bbbind.com/free-tsb Enter vehicle info year , make , model and engine size . Under system click on HVAC ,then under subsystem HVAC controls will pop up . Click the search button , then the blue links . First off you need to know what system yours has , manual or automatic.
GMC Yukon HVAC Blower Motor Won Turn On
Blower Motor Problems Auto Repair Help

i beleive you did more than that.? you,ll probably find all have a common earth , chech and remove it , clean with a wire brush and replace, also chance the fuse you removed and replacer reguardless of it,s appearence , ensure its put back in the correct location,peter.

Check heater fuse.
If fuse good - could be a failure of the blower fan motor or blower control switch.
If fuse bad - bad blower fan motor could have blown the fuse.
DO: check fuse, then blower motor.
Pricing: new blower motor: Duralast PM270 $43.99
new heater control switch: Duralast SW229 $46.99 (without
A/C).
I'd expect your blower resistor to be good - when they fail, the blower only will work on HIGH setting.

you might check your switch sounds like to me that your two lower speed sides of the switch maybe burnwed out.

check blower resistor it could be shorting out. try unpluging that and see if blower stops. hope the helps good luck.

Sounds like the fan control knob has shorted out. You can check the fan "blower" relay and fuse in the engine compartment but you need to make sure the control knob is good or you will keep blowing fuses and relays. If your blower fuse and relay are good, then just have the control knob checked and replaced if needed.

fan motor will not shut off

Yes,

there is 1 relay to work it properly,

so you ahve to check it with your regular multimeter,

this way you can do you solution ,

THNX