Pontiac Repair: heater problems, vacuum problem, vacuum source

Question
i have a 95 pontiac grand am se my question is what would cause my heater to go from hot to cold for 5-10 mins then back to hot and how would i fix this problem another thing is i only have 1 setting that works for the heater and that is the setting for the dashboard  i cant get none of the other ones to work can you please help me thank you

Answer
Hi
I would HIGHLY suspect a Vacuum problem. The HVAC system operates by vacuum controlled solonoids.
Your problems mirror the problems that occur when there is a vacuum problem.
PROBABALLY the vacuum source line somewhere between the engine and the controller.
I do not have manuals for 1995 models, so you MAY want to check with a good competent shop your familiar with.
Hope this helps
Pawl