Pontiac Repair: 99 pontiac montana hacv, hand vacuum pump, upper intake manifold

Question
QUESTION: Thanks for your time and mind,i am working on a 99pontiac montana w/3.4.The a/c is blowing cold(45 f), proper pressures but not much speed out of the vents.Is there a vacuum line or relay for the stepper motor defrost vent?  Q2  where is the fan temp switch on the same pos. thanks  chris

ANSWER: Hi
Believ it or not I just had one of these last week.
I found the Cabin Air filters (Located behind the glove box) were TOTALLY clogged and not allowing air flow out of the vents.
They were rather inexpensive, 20 bucks or so.
I am sure they'll be cheaper aftermarket.
The Mode, defrost, and temp. doors are controlled by engine manifold vacuum. The actual HVAC control head switches vacuum.
You can unplug vacuum lines from rear of controller and use a hand vacuum pump to check door positions and check for leaks.
Your Q2 I do not quite understand, the fan switch should be on the HVAC controller. It will send  voltage to the blower resistor on different circuits, which in turn varies the voltage through restistance to the blower motor.
If it is not working on a certian speed, check voltage with test light on all the circuits going to the resistor while turning the switch.
If they all light up when desired speeds are selected, the resistor is at fault (common problem).
I Hope this helps.
Please post back if more info is needed.
Good Luck
Pawl

---------- FOLLOW-UP ----------

QUESTION: thanks for your timely reply,i just need to find the source of the vacuum for the switch from the engine.This vehicle just had an engine swap and i cant seem to find the vacuum line in the roomy engine bay.By the by i am pretty well versed in all early english cars,if i can help please let me know. thanks again shadetree

Answer
Hi
On the Upper intake manifold , Rear,  JUST at the corner where the Alternator bolts on there will be a vacuum port with the small vacuum line your looking for.
If I'm not totally mistaken, It runs OUTSIDE of the loom, so you should be able to follow it.
I hope this helps.
Good luck, and please follow post if I can help!
Pawl