Description
2008 Pontiac grand prix , blower on heater works , will not blow hot even though temp is set on hot , now and then the temp gets close to over heating , whats the issue with the temp not getting hot and motor getting almost hot enough to over heat ?

Explanation & Answer

If the fan runs, but there's no heat, it's probably the thermostat which would also cause your vehicle to overheat. This would cause your symptoms for both issues you are experiencing.
