moran75

1965 heater control cables ‘sabotaged’?!

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Hi All

 

Bear with me on this lengthy background - the straightforwad enough questions I have are at the end...

 

I do have a manual and the section re combined heater/air con system is quite a read ...so before I get stuck in can I pick your brains...

 

Current situation is :

1) heater/defroster controls can only be moved from halfway point to full on. Cannot be moved from halfway to off position .

2)blower doesn’t work

3)no noticeable heat produced 

4)air con blower works...both levers have free movement ...when blower on and levers sent to max I have air but not cold

 

So when i I bought the car it hadn’t been used for years. The seller told md the previous owner had ‘deliberately cut the control cables for heater short’ - hence point (1) above. He didn’t know why someone would do that but was adamant about it.

 

Question 1)  if the info given was correct does anyone know why anyone would want to deliberately stop heater control cables being switched off? Is it an old skool trick to prevent something ‘bad’ happening, with perhaps a failing heater core? Or anything else....

 

By the way I can can live with current situation re heater levers/lack of blower/heat ....

 

BUT

 

question 2) i’dlike the A/C to work. Before I top up refrigerant will the fact that heater levers can’t be pulled to off position mean A/C won’t blow cold even if system/refrigerant is good?

 

A bit long winded I know...but I got to the point in the end!

 

cheers

 

kev

 

 

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1. The heater control cable can be adjusted.  Perhaps it was "shortened" by turning the adjustment excessively.

2. Disconnect the cable from the heater valve.  Make sure both the cable and valve work freely, then test the heater by opening it manually.  Lube them both.

3. Manually close the heater valve to test the AC.

4. Heater and AC blower controls go to the same place.  If the blower works on AC/vent, then the problem is likely with the controls.  Pull the controls from the console and make sure the harness is connected to the heater fan switch.  Note: it's a 4-speed blower, but AC/vent uses the top three speeds while heater/defrost uses the bottom three.  You can fix that.

5. Test the diaphragms on the blower box.  There's a chart in the manual that lists which diaphragms are open on each control setting.  Go through the list and make sure everything's working right.  If a diaphragm is supposed to be engaged, grab the control rod and pull it to make sure it has travelled through the full range of motion.  If things are stuck or hard to move, pull the blower box and clean, lube, and reseal everything.

6. Before pumping a couple of pounds of expensive R12 into an unknown system, check the drier window for bubbles.  If everything else is working and you don't see any bubbles, you might guess that the system is empty.  If that's the case, vacuum test it and install a new drier before filling it.

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47 minutes ago, KongaMan said:

1. The heater control cable can be adjusted.  Perhaps it was "shortened" by turning the adjustment excessively.

2. Disconnect the cable from the heater valve.  Make sure both the cable and valve work freely, then test the heater by opening it manually.  Lube them both.

3. Manually close the heater valve to test the AC.

4. Heater and AC blower controls go to the same place.  If the blower works on AC/vent, then the problem is likely with the controls.  Pull the controls from the console and make sure the harness is connected to the heater fan switch.  Note: it's a 4-speed blower, but AC/vent uses the top three speeds while heater/defrost uses the bottom three.  You can fix that.

5. Test the diaphragms on the blower box.  There's a chart in the manual that lists which diaphragms are open on each control setting.  Go through the list and make sure everything's working right.  If a diaphragm is supposed to be engaged, grab the control rod and pull it to make sure it has travelled through the full range of motion.  If things are stuck or hard to move, pull the blower box and clean, lube, and reseal everything.

6. Before pumping a couple of pounds of expensive R12 into an unknown system, check the drier window for bubbles.  If everything else is working and you don't see any bubbles, you might guess that the system is empty.  If that's the case, vacuum test it and install a new drier before filling it.

So...quite a lot to get my head around...so bear with me...am I right in saying that if I don’t repair /adjust the cables, leave the heat/defroster levers as is - midway - and leave heater blower off...then even if all A/C system is perfect (just for arguments sake) then it won’t work properly because of the possibly engaged heater valves/diaphragms etc?

 

or if the heater system is just not working at all, for what ever reason ,then I could repair A/C and use it as per normal despite the heater problems?

 

thanks

 

Kev

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12 hours ago, moran75 said:

So...quite a lot to get my head around...so bear with me...am I right in saying that if I don’t repair /adjust the cables, leave the heat/defroster levers as is - midway - and leave heater blower off...then even if all A/C system is perfect (just for arguments sake) then it won’t work properly because of the possibly engaged heater valves/diaphragms etc?

 

Yes.  If you want the AC to work optimally, the heater valve (vacuum control) and heater temperature door (cable control) need to be closed.  The heater air door (vacuum control) needs to be open.  I have no idea how your allegedly boogered cables may affect operation, but both the valve and door need to be closed.  IIRC, the valve will close without vacuum, but you'll probably want to verify that and confirm that it's not stuck open.  You need a working diaphragm to open the air door (or remove the diaphragm, pull the door open, then clamp the control rod to hold it open).

 

The heater valve controls the flow of coolant through the heater core.  The air door directs the air flow across the evaporator, heater core, or both.  The air door is controlled by a dual-stage diaphragm.  If the air door is fully open, all air goes across the evaporator.  If the air door is closed, all air flows towards the heater core.  If the air door is partially open, air flows both across the evaporator and towards the heater core.  The temperature door controls the amount of air across the core (as opposed to going around the core).

 

12 hours ago, moran75 said:

or if the heater system is just not working at all, for what ever reason ,then I could repair A/C and use it as per normal despite the heater problems?

 

Maybe.  You want the air flow to go across the evaporator rather than the heater core.  If the heater isn't working (plugged core, closed valve, whatever), you still need to make sure air is being directed across the evaporator.  If the air door is working properly, you can get full AC with an inoperative heater.  Having said that, you should get the whole thing working, if for no other reason than to be able to use the defroster.

Edited by KongaMan
change to reflect vacuum control for 65 heater valve (see edit history)
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1 hour ago, KongaMan said:

 

Yes.  If you want the AC to work optimally, the heater valve (cable control) and heater temperature door (cable control) need to be closed.  The heater air door (vacuum control) needs to be open.  I have no idea how your allegedly boogered cables may affect the position of the heater valve and temperature door, but both need to be closed.  You can close the valve and temperature door manually after disconnecting the cables, but you need a working diaphragm to open the air door (or remove the diaphragm, pull the door open, then clamp the control rod to hold it open).

 

The heater valve controls the flow of coolant through the heater core.  The air door directs the air flow across the evaporator, heater core, or both.  The air door is controlled by a dual-stage diaphragm.  If the air door is fully open, all air goes across the evaporator.  If the air door is closed, all air flows towards the heater core.  If the air door is partially open, air flows both across the evaporator and towards the heater core.  The temperature door controls the amount of air across the core (as opposed to going around the core).

 

 

Maybe.  You want the air flow to go across the evaporator rather than the heater core.  If the heater isn't working (plugged core, closed valve, whatever), you still need to make sure air is being directed across the evaporator.  If the air door is working properly, you can get full AC with an inoperative heater.  Having said that, you should get the whole thing working, if for no other reason than to be able to use the defroster.

Excellent ...1000 thanks 

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He's right, ya know.   I must have missed the part about it being a 65.  :(  The earlier cars had cable-operated valves.

 

In any event, the rest of the post stands.  Make sure the heater valve is closed when running the AC.

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