heater only blow semi warm air and only in defrost mode

[shroom]

hey i know theres a vac line for this, i have an open vac line running down the passenger side ontop of the manifold, i beleive its comming from the thermostat housing area, now where does it plug into ????, somewhere on the backside of the engine, or something comming off the firewall????, also, if you can help me on this one, my map sensor is mounted on the passenger side just underneath the air cleaner about halfway towards the back, now it has two nipples comming out of it, i have one line hooked in and it idles great, whats up with the other one