99 GSE heater/AC not working, 35-60mph major shuddering

[ElementCrush]

This is my GF's car that I have the unfortunate displeasure of driving occasionally, and I have to say although my 95 Integra has had it share of tows, her's is a consistent problem.

First problem is the interior heater and A/C fan. For awhile (maybe a year and a half) the fan had a squealing issue and would work but make quite a racket for a few minutes before shutting up. Now the A/C and heater has gone AWOL entirely, and when she asked her uncle about it he said the heater core is probably going out.

I call bunk on this for a couple reasons: My 95 Integra's heater core died last winter at the worst possible time. It did the usual fogging-up of the windows and overheating the engine along with leaking into the floorboard, so I cut the hoses to it and did a bypass for the time being. Her car doesn't have the fogging or overheating problem, but it does create a pool of water ever time it rains although that's probably not related. It doesn't overheat either.

Second, I can feel a slight bit of heat coming up from the defroster on the dash, and when I try to engage the heater with the controls, the light for it just goes off after a second or so, making me think this is purely electrical.

I don't want to replace the heater core if that's not the problem, so what gives?

Part two is a bit different... her car bogs down hard and shudders like mad when you hit 35 and will continue to do so until it makes it's way to about 60mph or so (it's a real chore to get it up to that speed). The spark plugs and wires I replaced about 2 years ago, and this car isn't driven much. Stuff I've read about this issue make it seem like just the fuel filter needs replaced, but if that doesn't work, what else could it be?

[richtazz]

On the water issue, there is a drain for the HVAC unit (to allow condensation that collects from the A/C evap core to escape) that sticks out the firewall that could be plugged with debris (especially if the cabin air filter has been neglected). Another known issue with these cars is the seal that goes around the cover over the HVAC air intake/cabin air filter. It can come loose, allowing water to get in from the bottom of the cowl area, especially during hard rain. This water gets into the blower motor and is probably the cause of the squealing.

[ElementCrush]

Alright, I'll take a look at that.

I checked the fusebox on the right of the passenger dashboard (where it meets up against the door) and found one of the small fuses for the HVAC unit was missing. Can't remember which one, but I used the spare and that made it so the lights for the controls and such stayed on instead of going off after 3 seconds.

Turning on the car in a quiet area, I tried to use the heater and A/C units then, and it seemed to be trying to do something, like the engine was straining a bit. Changed the tone of it at least, but nothing came out. Makes me think that indeed the blower went bad and the seal you mentioned is the main culprit, so I'll pull out the unit and see.

I found this place to have it the cheapest:
1999 Buick Regal Heater Blower Motor with Fan Cage at 1AAuto.com

Any thoughts on them? If you know of another deal, it's the model with the automatic/digital HVAC controls (VIN 1 series I guess).