it runs from the latch and down the n/s a pillar. the front roof panel unscrews with torque srews
Can be a hole in the radiator or a problem with one or more of the hoses. A mechanic can run a pressure test to see where the problem(s) are located at.
I have the same problem with my 93 Chevy suburban also, and I found that the rear has a separate heater core located behind the rear right wheel well. From what I understand you have to locate it, and test it, and then flush it if the hoses are clogged.
Radiator hoses? Heater hoses? Vacuum hoses? EVAP hoses? Need more info to help you.
While facing the engine, the filter is located left hand side of the firewall. it's black, cylindrical w/ 2 hoses sticking out of it. Very easy to locate and replace.
Vents crankcase via carb vac. Typically valve cover/similar. Check your vac hoses & that should help you locate.
The fuel filter is located on the passenger side near the firewall. It is a silver-colored cylinder with hoses on each end. You have to disconnect it from the car and try to pull it out far enough to pull the hoses off. My 1993 had really short hoses and it didn't come out far enough to change the darn thing by myself. Hopefully, they fixed the problem by 1995. Steven
Chevy Ventures have two heater hoses. One is located on the intake connection and the other located on the output connection.
Locate hoses under hood that go to the heater core. there should be 2. They are rubber hoses, smaller than the radiator hoses. after you have located them, leave hood open, start the car. Feel the hoses as the car warms up, one hose is an inlet to the heater core, one hose is an outlet. if one hose gets hot and the other does not, then the heater core is restricted, and may need replaced or flushed.
There are many vacuum hoses, consult a repair manual.
Locate where the heater hoses go through the firewall. The evaporator is usually located close to there. Look nearby for a rubber hose or it even might just look like a rubber plug in the firewall.
Could be blend door issues. With engine warmed up, running and coolant level is full, open the hood and locate both heater hoses. Feel the hoses with your hands. If both hoses are hot you probably have a blend door problem. If one hose is hot and the other is only warm or cold you probably have a plugged up heater core, try flushing it. If both hoses are only warm you may have a faulty thermostat, replace it.
Try heater hoses.