UPDATE: I'm getting FC 21/22 on the manual diagnostic which indicates sunlight sensor failures... is this important?

Geez, If it's not one thing its ten others with this car! First cold day of the year since I've gotten it back on the road and noticed the heater ain't working and the air flow just plain sucks. When using the AC it works reasonably well and I get a bit somewhat better air flow, but when temp is cranked up to HI, air flow slows to barely anything, and I get just a little lukewarm air. This is true for all vent options. I've opened the glove compartment and watched the linkages and they do seem to move well and cleanly, pics attached (first is set to HI, second is set to LO) both AUTO is off.

I suspecting the heater matrix is clogged. Under the hood, both inlet and outlet pipes are HOT however, with or without the heater running, and the matrix feels pretty hot to the touch sometimes, but sometimes not. I can't figure out why it's intermittently hot or cold. UPDATE: Pretty sure this is the problem as when I got the car it needed a head gasket job and I noticed there was a TON of radiator stop leak product floating in the resevoir. I'm betting it gummed up or reduced the performance of the heater core/matrix.

Think I'm going to pull both hoses off the inlet and outlet pipes under the hood and run water through them with a water hose just to check the flow. Am I right in assuming I should see flow? There's no check valves or filters on the run through the firewall is there?

ANy other ideas? And why my air flow is so weak?


Temp ON HI

Temp on LO

 

Yes you have that right.
......

 

Ok, flow inside the heater core was perferctly fine. Not clogged at all during the flush. the problem was about 2lbs of leaves and debris stuck in the blower fan and piled up behind the heater core! Thats why the AC would work, but not the heater. The flip to the AC vent is above the heater core and all the debris... So, I pulled out and cleaned the blower fan and blew out the housing with a leaf blower, reinstalled and everything is working great!

 

Sounds like you're missing the filter strip for the air intake if that much crud is getting in there.