Heater HELP!

[Crank]

Hey fellas. Okay I need some help. I just replaced the heater core in my truck a week or two ago. I figured this would fix my heat up all dandy like, apparently not. When I switch it on, the blower motor turns out all cold air. The heater lines are all hooked up, no leaks, and the bottom cold/hot switch, when you move it over, I can hear the door flapping. The fan switch works from Lo to Hi, but when I turn the actual selector, it doesnt change anything. On heat, it doesnt blow heat, defrost, no heat out of the top vents, The only thing I could think of it being would be the control panel is bad, or something isnt working in one of the vacuum actuators... Does anyone have any insight or help that can get me to fix my heat, it was 35 in NC this mornin. Thats cold folks with no heat. PLEASE HELP> Thanks everyone
Brandon

[petemonster]

what year truck is it?
sometimes the defrost vent hose will fall off on older models
make sure to get a new radiator cap..this can cause probs...for 6 bucks you cant go wrong.
also you may have a critter nest or something blocking the vent door in the heater box.

[krue]

Make sure the heater hose is getting hot.

[Crank]

Truck is '86, as listed in sig, new rad cap. thanks fellas I'll look at it later this evening
Brandon

[Crank]

Also, I cleaned out the heater box, well there wasnt anything much to clean out... BTW, which hose connects where on the heater core? I think i have the larger going back into the rad, and the small 5/8" going into the water pump. Is this correct? Could it cause a problem? I'm stumped. Thanks fellas
Brandon

[us111]

possibility t-stat could be stuck open but even at that you would get a little heat,,easy enough to check,pop it out and throw it in a pot of boiling water to make sure it's working correctly..

[Crank]

K. New radiator, cap, thermostat, heater core. All new, New lines. I even replaced the stat with a 180* cuz I couldnt get my pig to cool down. I'm sure that will effect it, but not enough to matter. Does anyone know the configuration of the lines from supply to which fitting on heater core 3/4 or 5/8" then which fitting to return? I cant figure it out
Brandon

[piecesparts]

The 3/4 is the return to the radiator tank and the 5/8 is the supply from the intake connection.

[Crank]

Hrmmmm. Wonder if that'll make a difference in heating?
Brandon

[boxrodz]

Ditto on what piecesparts said about the intake and return hose. Once the engine warms up, feel each of the hoses. Both hoses should feel very warm to the touch, but the intake hose (5/8") should feel warmer. If the heater core is warm, then the air door is probably not swinging open in the heat position and all you feel is normal (cool) air. I'd check the door operation.

[7387chevys]

My heater is funny like that have to slide the button back and forth a couple times to get it up on defrost.............If you cant get it fixed use some redneck engineering..............duct tape, power inverter, hair dryer.......see where I'm going with this...........
Shane

[Crank]

Power inverter/Space heater is more likely, I think that would actually work pretty well. I'll try those fixes to see if it'll work first.
Brandon

[Bender]

I actually bought a brand new thermostat once that didn’t work, ever since I always test them in boiling water before I put it in.