Ive looked at both and neither move,the temperature never changes, the fan speed is the only one that works, also, when I had my car into the dealership this summer for the air conditioning they replaced the Dash Control Unit (part # 25732792) Ive pulled that out and inspected that, although there isnt much to really inspect.

The HVAC BATT fuse was good? Also check the HVAC fuse. They are both in the rear fuse block and both 10 amp fuses.

Both checked out good.

There are three door actuators: mode, air temp., recirc. All three actuators and the HVAC control module are supplied power (batt+) from the HVAC fuse (10A) in the rear fuse block. The actuator position settings are precalibrated and non-adjustable. Just a quick check with a multimeter. Remove the the most accessible actuator connector and measure voltage from pin #10 (brown wire) to ground. With ign. on there should be a constant 12 vdc. If you could check the other two actuators, that would help. The other thing to do is remove the HVAC fuse from the rear fuse block, select low ohm scale on meter, then meter to ground the load side of the vacated fuse socket to check the actuator circuit & HVAC cont. module feed is above ground. Try those couple of things. Since your blower motor is operating normal, I'm leaning away from the fact that the HVAC control module is defective. But that doesn't mean it isn't. Try to check the simple things first. As a last resort, you may want to take to GM dealer, they can put a scantool on and interrogate the HVAC control module for current or past history DTC'*.

I might have missed it reading through this thread, and I apologize if I have, but have you checked your coolant level? A common cause of intermittent heat, or no heat, (and the fact that one of the hoses is not hot) is low coolant. Check the coolant level cold at the radiator, not the overflow. Normal flow through a good heater core will have both hoses hot, with the return hose slightly cooler than the other. On my '95, the heater core feed hose is the top hose from the tensioner assembly and the return is the bottom. If your ducting is not allowing air flow through the core (no heat) and the coolant flow through the core is OK, both hoses should be pretty much the same temperature of "hot" since there is no significant heat being removed by air flow through the core. A trapped air bubble in the cooling system can also prevent proper flow through the heater core causing a poor heat problem. Has the cooling system been opened but not properly bled?

I did the voltage test on the actuators... the 12vdc is there. I am not sure what the exact issue was with the control module when they replaced it this summer, I do know that the blower fan worked when I took it in, I never had any temp control then either.

I was afraid to suggest this because of the negative feed back, but....I would recommend that you back flush the heater core and go from there.

Removed the air temp actuator tonight and manually moved the temp control...when I moved it myself I have heat. When I reconnected the actuator it would not engage back to that mode. I ran a voltage test on it and it appears to have normal voltage. The actuator itself looked fine, no slipped gears or anything. So for now I have heat. Any ideas?

I recently had the same problem. The a/c shop replaced the actuator and the heater is working just fine now. However, I am a little afraid that the problem has not fixed because it failed again during the weekend.

I am concern that the heather is working just fine now and it is hard to diagnose when the problerm is not present.

I will stay tuned for further information on your problem.