it's cold here in pa. and i go to turn on the heater in my 93 LT1 c4 and i have it set to 90* and i just don't fill the heat, the fan comes on with auto and fan over ride, my temp gage reads 205* and there are no leaks, whats going on? any one with any help will most appreciated ,

Sounds like the blend air door, or damper, isn't working. I never palyed with mine, but I understand you can see it by removing the controller on top of the evaporator housing on the motor side of the firewall, passenger side.

thank you , i'll take a good look at that after work and let you know, it's a start and thats more than i had.

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Yea, it has to be the door or controller because there is always hot water in the heater core (no shut off valve in the heater core lines).

ok, would a fuse maybe out?

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Very unlikely it's a fuse, much more likely it's an issue with the vacuum system that controls the hvac or a mechanical issue with the dampers, as previously noted. Usually if it's a vacuum issue you get heat all the time though :-)

thanx Bogus, you the man

thanx Bogus, you da man

Is this a new issue? I don't know how long you've had the car. Is the heater core bypassed?

Is this a new issue? I don't know how long you've had the car. Is the heater core bypassed?

i'v had the car for a month and there is some heat i felt on a warmer day when i forgot to turn it off, just enough to let me know it was on.

Are you sure that wasn't just radiant heat from the trans tunnel? Inspect the inside of the engine bay to make sure the hoses go to the core and aren't looped.

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I just had to do heater core bypass surgery on my car last week... Antifreeze chok'in me out ! No heater this time of year sux.

yep, no heat this time of year "sux", tomorrow i'll check more closely and make sure there is no bypass and also the blend door, as for having some heat when i had forgot to turn it off, when i did turn it off the fill of heat did stop.
thanx again for your help , i just hope is't not the heater core ,

ok, i checked all the hoses and there is none bypassed, must be the damping door, i'll have to check it when i get a fsm. thanx.

Remove the blower control module from the top of the heater box (inside engine bay, three screws) and you can peek in there and see if the door is physically moving when you change the settings on the control head.

If it's not moving, you need to do the step by step diagnosis to figure out why.

As a double check, make sure the hose coming out of the heater core feels hot when running, could be a blocked heater core.

thank you , i'll give it a look , this site is really a great help!!!!!

thanx matatk, that diagram is just what i needed , your a big help for this new vette owner .

heat trouble fixed, clogged core . had system flushed after i could find no problems through the great suggestions you all gave me. thanx to all!!

Wow... clogged core? That's rare.

Usually the cores leak long before they clog.

Good catch! Now... hope you get through the winter without leaks!!

Glad you got it fixed!

thanks all, being new to vette all the help i got was great!, nice and warm now and also fixed the ABS/ARS lights that would come on and then go out at restart was nothing more than low break fluid , they have not come on since .
GREAT SITE!!!

Thanks! Glad you like us!

And the more abstract problems we get, the better our archive gets!

As these cars age, we will start to see different problems, too...