Mitsubishi Repair: vaccum line, blower works, ventilation system

Question
Hello Anthony and thank you for being here.  My lady has a 2002 Mitsubishi spyder.  She has no heat at the windows, vents or feet.  the heater core has been replaced as well as the thermostat.  the blower works and the core is hot.  

I'm thinking she lost vaccum somewhere. the car was in an accident a few years back and that was the start of the problem.  the service center has never been able to fix it.  where can i check for the vac line from the manifold to the canister?

thank you very much
Mike

Answer
Mike,
Your fresh air vent may be stuck open or broken so too much outside air mixes with the hot air from the core and by the time it gets to the push out of the vents, there's very little heat.  If you change your vents to use recycled air (there should be a switch or button that will do that) and then you start to feel heat, then the problem is definitely with the fresh air intake vent.  Else, you may have a crack or opening in the ventilation system near the heater core and majority of the hot is being pulled out before it makes it into the cabin.  This is not something easy to inspect unless your service center has the ability to pressure test the ventilation system.
Good luck!