Heater Core maybe or maybe not
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Joined: Oct 2004
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From: ALEXANDRIA VA
Heater Core maybe or maybe not
Ok Vette guys and gals. I have no heat, the heater core is not leaking. I have heard the hoses might be clogged or somekind of sensor or whatever. Any ideas.
Next question??? Air is only blowing out of the dash (at the defroster
and on the floor not from the dash.
OOPS! 94 prettest red corvette you have ever seen!!
Electronic climate control
Next question??? Air is only blowing out of the dash (at the defroster
and on the floor not from the dash.
OOPS! 94 prettest red corvette you have ever seen!!
Electronic climate control
Last edited by JD JOHNSON; Oct 13, 2004 at 05:23 PM.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Air flow through the defroster only is a vacuum problem. Verify the integrity of the line from the source (for an L98, it's next to the fuel pressure regulator feed, past the left side of the distributor where it tees through a check valve). You should only be able to blow air through the valve one way; otherwise you need a new one. All GM's use this valve, so it's pretty easy to find a replacement.
Get the air flow right and then check whether or not there is any heat. If not, flush the core by disconnecting the hoses and hooking up a garden hose to it or use compressed air.
Blower problems are best checked by jumpering the blower motor directly to the battery. If stronger, you need to troubleshoot the blower module (electronic air) mounted on the evaporator case. Input is the tan wire and it should have about 2 volts on it for low blower speed, 7 volts on it for high. If it doesn't, there is a problem with the wire or Programmer or Dash Assembly. If the voltage is correct, see what's being sent to the blower motor. It's the purple wire and should have 4 volts for low, 12 volts for high. If it doesn't, the module is bad. Verify voltage at the blower motor too to make sure that the wire is ok. You should also check the connector. A tired blower motor draws a lot of amps and the terminals are crimped, not soldered. This can cause a voltage drop and if the wires are discolored, take apart the connecter and solder the terminals to make sure the blower is getting full voltage.
If the voltage is right and it doesn't blow any stronger jumpered to the battery, the evaporator core is plugged or the duct work is leaking.
Get the air flow right and then check whether or not there is any heat. If not, flush the core by disconnecting the hoses and hooking up a garden hose to it or use compressed air.
Blower problems are best checked by jumpering the blower motor directly to the battery. If stronger, you need to troubleshoot the blower module (electronic air) mounted on the evaporator case. Input is the tan wire and it should have about 2 volts on it for low blower speed, 7 volts on it for high. If it doesn't, there is a problem with the wire or Programmer or Dash Assembly. If the voltage is correct, see what's being sent to the blower motor. It's the purple wire and should have 4 volts for low, 12 volts for high. If it doesn't, the module is bad. Verify voltage at the blower motor too to make sure that the wire is ok. You should also check the connector. A tired blower motor draws a lot of amps and the terminals are crimped, not soldered. This can cause a voltage drop and if the wires are discolored, take apart the connecter and solder the terminals to make sure the blower is getting full voltage.
If the voltage is right and it doesn't blow any stronger jumpered to the battery, the evaporator core is plugged or the duct work is leaking.
