No heat across the front dash..in My 99 Catera

[adaddo]

Hey there...
Hoping for any words of wisdom as to why No Heat ...only cold air...from the front vents, dash, floor and defrost.
I believe I've checked alot of the basics
As for history...Car had sat for several months, with a "continuing battery drain issue" Dealer states 0 to 380 milliamp intermittent draw.
But, for now...replaced the battery, only to find that the only heat is coming from the small vent in the back seats, at the rear of the center console.
Took to dealer...who stated this Installed scan tool - History 35 AC Requesting High and 38 TW/Solar Sensor Supply High Voltage. Diagnose Faulty HVAC Control Head.
Couldnt afford the 900.00 for a new one...so bought one on-line.
Now, once installed....the fan no longer jumps into super High fan mode....But cold air remains from all but the rear vent. I did the reset, thats suppose to recalibrate the doors...pushing both control knobs for 5 seconds.
The heater hoses appear hot, the car operates at normal temps., etc.
I did have a new Heater control valve put in last year..Could they have hooked the hoses up wrong? Or possible that both doors that control air to the front...are stuck closed...from sitting?
Was just hopin that someone might have an idea...without returning to the dealer for the next 85.00 scan
I did notice that the a/c compressor isnt kicking on...do i need a operational a/c system in order to have heat?
I'm thinkin maybe blend door actuaters....but i believe there are at least 2...both of em going out at once?...dunno
Any help appreciated
Thx
Adaddo

[lakesidepark]

the two temp actuators for sure...the cog on the end of the small motor shaft will slip forward and miss the cog for the blend door. Then it will not turn the door. I removed both of my motors, found an item small enough to place on the rear of the motor shaft, then "tapped" the cog back down until the shaft was flush with the top face of the cog. Do not tap the shaft without securing the back side (small hole to see rear of shaft on back of motor) - secure this with a small pin that inserts into the hole and rests against the shaft so the force is not applied to motor housing or you may distort the motor.

Heater Control valve - If you swapped the output hoses, the heat will not come on unless the AC is on HIGH (60 degree setting). The HCV is supposed to stop the flow thru the heater core only on max AC. Plumb it backwards, and all you get is a small blast of warm air before it turns cold when it is on heat.

[adaddo]

thx Lakeside
any idea how to access (or locations) of the actuators?
any diagrams?
thx

[adaddo]

Hmmmm...
Was just told that i need to take the car to the dealer...or someone with a Tech 2 Scanner following the heater controls replacement.
Anyone know if this is true?
Shouldnt i be able to just replace the heater controls....reset the actuaters, and it work?
Any help appreciated
Thx again