Heater stopped working

[gnilson]

I have no heat at the front of my 2001 Yukon but the rear has plenty. I replaced the diverter motor twice and that did nothing. Is there a control valve for the front that is separate from the rear?

TIA
Geoff

The A/C works fine.

 

[bottomline2000]

heater core may be clogged. check the hoses running from the water pump to the firewall. if one is cold that is your problem..

 

[gnilson]

Is there a separate heater core for the rear? I have good heat in the back. That being said, I have not flushed the cooling system in 5 years, so it is way past time.

 

[08HoeCD]

Two separate heater cores for vehicles with rear heat/ac.

 

[retiredsparky]

If you look dead center above the motor at the fire wall, you will see the heater hoses and two tees. That is where the rear taps off to run back to the other heater core. A bad design, with o-ring seals, prone to small leaks. You can either use an infrared temp device to monitor the temp or just feel the tee-there should be a temp differential, but still all three sides of the tee should be warm or hot. I agree, blocked heater core is likely.