Heater Control Valve Location
Thread Starter
Drifting
Joined: Oct 2003
Posts: 1,348
Likes: 18
From: Dallas Texas
Heater Control Valve Location
HI
does anyone know where the heater control valve is located - it is not listed in my book.
Also what is the thing that is down in the blower housing - it sits on the top of thehousing and hase two electrical connections - when you take it out it has a rounf black module on an metal plate with vanes, what does it do?
Thanks
does anyone know where the heater control valve is located - it is not listed in my book.
Also what is the thing that is down in the blower housing - it sits on the top of thehousing and hase two electrical connections - when you take it out it has a rounf black module on an metal plate with vanes, what does it do?
Thanks
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Your profile says you have a 93 and I think that heater temp control is done by a door in front of the heater core and not by a valve as the earlier C4's used.
The module in the housing may be the heater motor resistors. They control blower speed and use airflow to keep them cool.
You didn't say which A/C system you have; standard C60 or the electronic C68 system??
The module in the housing may be the heater motor resistors. They control blower speed and use airflow to keep them cool.
You didn't say which A/C system you have; standard C60 or the electronic C68 system??
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
As posted, the '93 doesn't have a valve controlling coolant flow to the core - coolant is always present at the core as it bypasses the thermostat.
The item you described is the blower control module which is used with electronic air. It's an amplifier that gets low voltage signals from the Programmer and increases them for blower operation. It also provides a ground for the compressor when a/c is commanded.
A/c/heat temp is controlled by a door that block/allows airflow across the Evaporator and Heater Core. The door is contolled by an electric motor.
The item you described is the blower control module which is used with electronic air. It's an amplifier that gets low voltage signals from the Programmer and increases them for blower operation. It also provides a ground for the compressor when a/c is commanded.
A/c/heat temp is controlled by a door that block/allows airflow across the Evaporator and Heater Core. The door is contolled by an electric motor.
Thread Starter
Drifting
Joined: Oct 2003
Posts: 1,348
Likes: 18
From: Dallas Texas
Heater no Heat
Many thanks for the replies
so if I am not getting any inside heat then its a thermostate or a door that is not working..is that the general impression?
Would running the codes tell me if there is a problem?
Thanks
so if I am not getting any inside heat then its a thermostate or a door that is not working..is that the general impression?
Would running the codes tell me if there is a problem?
Thanks
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
My 92 service manual does not show a heater control valve in any of the schematics, only a temp door in front of the core. My 87 does have an in-line valve on one of the hoses that is operated by a vacuum signal from the heater control lever.
There is a sort of control valve that operates the temp door and that may have been what was repaired in Lichen's case. It's a small vacuum motor and is a common problem when there is no heat or all heat.
If you have the electronic HVAC system, are any of the indicator lights flashing?? They have their own set of codes and can be shown on the Climate Control display. There is a specific code for Temp Door Circuit Fault.
Push and hold the fan up and down arrows at the same time until the display reads 00. This is the diagnostic mode and you can select any of the parameters by using the up and down arrows. To see the value for that parameter, just hit the fan "Auto" button.
If the tem door motor is bad, Parameter 0 will show an 01 or 02 fault.
There is a sort of control valve that operates the temp door and that may have been what was repaired in Lichen's case. It's a small vacuum motor and is a common problem when there is no heat or all heat.
If you have the electronic HVAC system, are any of the indicator lights flashing?? They have their own set of codes and can be shown on the Climate Control display. There is a specific code for Temp Door Circuit Fault.
Push and hold the fan up and down arrows at the same time until the display reads 00. This is the diagnostic mode and you can select any of the parameters by using the up and down arrows. To see the value for that parameter, just hit the fan "Auto" button.
If the tem door motor is bad, Parameter 0 will show an 01 or 02 fault.
Last edited by c4cruiser; Dec 28, 2004 at 02:35 PM.
