Heater doesnt work...not like it matters...
Thread Starter
Instructor
Joined: May 2004
Posts: 184
Likes: 0
From: San Francisco Ca
Heater doesnt work...not like it matters...
Well im going through my entire car and trying to fix anything that is broken. One of these such things is the heater. I have a 92. Even when i push the temp up all the way to 90 degrees it doesnt heat up at all. Any thoughts?
Le Mans Master
Joined: Jul 2001
Posts: 8,182
Likes: 3
From: Santa Maria, CA
Hi philly,
one thing to check is the vacuum supply to the HVAC controller. The system needs vacuum to work. Vac is supplied from the engine. Look for a leak on the tubing or on a fitting on the line that feeds the vac to the controller. It should be near the back of the intake plenum(engine).
You may want to flush the heater core and verify it's not clogged/and allowing hot coolant to flow thru it and not just over it.
Be very gentle handling those core hoses/pipes. At their age by now, they are weak and you don't want to break a heater core pipe. It would be a major PITA to replace the heater core.
Let us know what you find.
one thing to check is the vacuum supply to the HVAC controller. The system needs vacuum to work. Vac is supplied from the engine. Look for a leak on the tubing or on a fitting on the line that feeds the vac to the controller. It should be near the back of the intake plenum(engine).
You may want to flush the heater core and verify it's not clogged/and allowing hot coolant to flow thru it and not just over it.
Be very gentle handling those core hoses/pipes. At their age by now, they are weak and you don't want to break a heater core pipe. It would be a major PITA to replace the heater core.
Let us know what you find.
Last edited by pablocruise; Jul 11, 2005 at 05:15 AM.
Instructor
Joined: Apr 2005
Posts: 120
Likes: 0
From: Port Angeles WA
Originally Posted by philly1919d
Well im going through my entire car and trying to fix anything that is broken. One of these such things is the heater. I have a 92. Even when i push the temp up all the way to 90 degrees it doesnt heat up at all. Any thoughts?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Vacuum has little to do with whether or not you get heat. The door that controls heating/cooling is either actuated by an electric motor (electronic air) or a cable (Manual Air). To see if the door is moving remove the Blower Module (Electronic Air) or Resistor Pod (Manual Air) from the Evaporator Case and look inside. Then, as someone operates the controls, make sure the door moves from heat to cool and cool to heat. If all is well, the heater core is probably plugged up. If it is, the rest of the cooling system may be plugged up too, so it's good idea to fix it and make sure the system is clean. You can try flushing the core with water from a garden hose or by using compressed air. If neither works, you'll need a new core.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by SunCr
The door that controls heating/cooling is either actuated by an electric motor (electronic air) or a cable (Manual Air). To see if the door is moving remove the Blower Module (Electronic Air) or Resistor Pod (Manual Air) from the Evaporator Case and look inside. Then, as someone operates the controls, make sure the door moves from heat to cool and cool to heat.
what would the fix involve?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If it's electronic air, usually the plastic linkage between the motor and the door is broken. Easiest to access with the ECM removed. If it's manual air, it's controlled by a cable from the dash to the heater plenum and generally the cable has broken, but I've seen some GM dash units (on other models) broken behind the **** or push bar.
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2nd Gear
Joined: Jul 2005
Posts: 2
Likes: 0
1989 C4 L98 HVAC Stuck in Heat only mode
Originally Posted by SunCr
If it's electronic air, usually the plastic linkage between the motor and the door is broken. Easiest to access with the ECM removed. If it's manual air, it's controlled by a cable from the dash to the heater plenum and generally the cable has broken, but I've seen some GM dash units (on other models) broken behind the **** or push bar.
