Having problems with your 2000 GMC Sierra ?
Only blows out cold air on all setting - 2000 GMC Sierra
Check on the back side of the heater control knob, the adjustment wire may have come loose, if it has just replace the c clip on it and it should work fine. If the knob is functioning properly, check your coolant level, if the coolant level is good it might be time to replace your thermostat.
Repair Help & Product Troubleshooting for 2000 GMC Sierra
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