Have a 1990 corvette L98, I have no heat at all. When u turn the controls on all u get is cold air blowing through. Does anyone have suggestions on what it might be.

 

ok, do all the vents work as they should? electronic a/c or manual?

is there vac to the cabin to operate the vents?

Assuming that these items are in good shape and there IS vac and the vents DO actually open/close by way of the diaphragm actuators hidden in the dash, it MAY be a problem with water flow to the heater core.

are the heater hoses TO and FROM the core intact? is there a water control valve inline at the core/evap? If there IS a water valve, is it working when you select heat and raise the temp controls?
for a/c it should close, for heat it should open allowing water to circulate.

can you tell if there is hot water flowing to and from the core thru the heater hoses?

is there a 180 t-stat in the engine? you will get ZERO hot water to the heater if there is NO t-stat. The engine must be at least 160 or more to have enough hot water to provide anything to the cabin.

so, you need to check hot water flow under the hood, then see if there is a vent issue in the cabin. If hot water is actually circulating and entering the core, its then a matter of vent doors opening and closing in the right sequence to get any warmth in the cabin. Cores fail, people bypass them because they are a PITA to change out.

Vent/blend doors stick and actuators fail. This is WHY we buy FSMs to see where these are and learn how to test for individual vents/doors and actuators to isolate and ID the malfunction.

 

If car has manual C60 HVAC control....H/C slider do your hear door hit stops when lever is moved from hot to cold? Either way the temp door is behind dash glove box, if removed you should be able to see either cable or actuator operate door. C60 is manual and C68 is automatic or electric climate control just for reference.

 

I have electric

 

I've had 2 cars that had airlocked heater cores. Both were bears to get bleed out. Had another that had 'vacuum' lines that controlled the heater and ac. That one the control had separated so the vacuum was being lost and not controlling anything.

Is this recent and have you done anything with the cooling system lately? How is the engine temp - any change lately? Any change in coolant level lately?

 

I wish it was that simple. The reason I don't have heat. Is because the heater core was bypassed, the reason why the heater core was bypassed. Is because it's leaking . I reconnected the lines, then I smelled coolant. I looked under the passenger side and found coolant dripping.

 

cores are cheap. The work LOOKS intimidating...but its not that bad.

http://forums.corvetteforum.com/c4-t...etty-easy.html

there is another useful thread right near this one...this weeks list.

 

Thanks, a lot of the post are for a 1984-1989. Mine is a 1990,it's totally different. I actually found something on the corvette registery.
QUOTE=leesvet;1585686477]cores are cheap. The work LOOKS intimidating...but its not that bad.

http://forums.corvetteforum.com/c4-t...etty-easy.html

there is another useful thread right near this one...this weeks list.[/QUOTE]

 

Finally got the heater core replaced. 350 dollars later. I have heat in my car.