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The previous owner of my 1981 280ZX said that the heater was “disconnected” so it won’t work. I would like to reconnect the heater so it works, but can’t seem to find much help online with this. How would I go about reconnecting this? I have most dash panels off so I can see inside where the heater core is, but I’m not seeing anything disconnected.
 

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1983 280ZX Turbo
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Look under the hood. I'll bet the water line to the heater is disconnected or blocked. One failure point is the water valve inside the car, and someone might do the dumb thing and block the water to it instead of fixing it.
 

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Look under the hood. I'll bet the water line to the heater is disconnected or blocked. One failure point is the water valve inside the car, and someone might do the dumb thing and block the water to it instead of fixing it.
The heater tube and valve is open, but there is this tiny tube right next to it that is cut and closed with a screw, could this have something to do with it?
107321
 

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1983 280ZX Turbo
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I believe that's a vacuum line. But right beneath is a shutoff valve that does NOT belong in that car. What is it shutting off? Looks like it may be in the hose to the radiator.

I don't have my car handy to check. Someone else will probably help.
 

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I believe that's a vacuum line. But right beneath is a shutoff valve that does NOT belong in that car. What is it shutting off? Looks like it may be in the hose to the radiator.

I don't have my car handy to check. Someone else will probably help.
I checked and I believe that is the heater tube, and someone put a shut off valve in afterward at some point, not sure why though. Also the tube has “heater” written on it.
 

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I checked and I believe that is the heater tube, and someone put a shut off valve in afterward at some point, not sure why though. Also the tube has “heater” written on it.
WOW! They left a clue! (That's worth a chuckle.)

Curiously, the position of that valve should be open, allowing water to flow. That seems backward from the idea that the flow is cut off.
 

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1983 280ZX Turbo
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May be using the valve to shut off in summer.
Perhaps; I suppose that's within the range of "previous owner weirdness."

I know I'd rather have that water circulating in the heater core rather than stagnating and corroding it during the summer.
 

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Update: IDK if this is what will get the heater working, but we found the hot to cold slider cable was disconnected so we reconnected it, I guess we’ll test it once the engine is ready to run
 

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"Is it plugged in and turned on" saves the day again.
 

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Which model of heater system do you have? Either a round knob to specifically control the fan on the right side of the heater controls which is the manual AC, (that's what you probably have) or a rectangular push button and on the face plate it will say Automatic Climate Control. Check to see if the heater valve is still hooked up to the hoses or not. See my enclosed pic of the original installed valve with the coolant hoses hooked up. The hose with a screw is the HVAC hose which controls heater functions on either model. That needs to be hooked back up to the correct source which is the control valve bottle in front of the RH strut tower. See my other pic. It would help if you could have someone else send you the hose diagram of the HVAC hoses out of the FSM. I do rebuild the original manual heater control valves if you need that done. Usually when I see someone adding that manual control valve in the engine compartment it's because they couldn't shut off the stock one under the dash, or they disconnected that valve because it was leaking and added the one under the hood. Z man of Washington 360-668-2979
zx heater valve 001.jpg
zx heater valve 001.jpg Vac Bottle CCair.JPG Vac Bottle CCair.JPG
 

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Which model of heater system do you have? Either a round knob to specifically control the fan on the right side of the heater controls which is the manual AC, (that's what you probably have) or a rectangular push button and on the face plate it will say Automatic Climate Control. Check to see if the heater valve is still hooked up to the hoses or not. See my enclosed pic of the original installed valve with the coolant hoses hooked up. The hose with a screw is the HVAC hose which controls heater functions on either model. That needs to be hooked back up to the correct source which is the control valve bottle in front of the RH strut tower. See my other pic. It would help if you could have someone else send you the hose diagram of the HVAC hoses out of the FSM. I do rebuild the original manual heater control valves if you need that done. Usually when I see someone adding that manual control valve in the engine compartment it's because they couldn't shut off the stock one under the dash, or they disconnected that valve because it was leaking and added the one under the hood. Z man of Washington 360-668-2979 View attachment 107352 View attachment 107352 View attachment 107353 View attachment 107353
Thanks for the pictures and detailed info. We found that we had an automatic climate control but it was disconnected and turned into a manual control some time ago by a previous owner. Would this HVAC tube still be what would make the heater work?
 

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If you look closely at the big pic of mine you'll see a rectangular black electrical plug in. That has to be plugged in with the proper harness when the conversion is done. When done properly the conversion is a major improvement. The controls in my main pic should be the one you're using now. The heater valve has to be hooked up just like the one in the pic however there is another mechanical valve that is still available that doesn't use the copper capillary tube in the pic. Notice the linkage running from the control valve. That has to be done properly also. The original valve for the climate control was a vacuum controlled unit. Do you have a mechanical heater valve mounted under the dash now? You have to have one of them, and you have to be using the mechanical heater controls with the round knob. The HVAC hose is still used to control the flappers under the dash. You need a single HVAC now, there was a pair of those hoses going through the firewall originally. To find out the hose routing you'll need a diagram from a factory service manual. You have to have the HVAC hoses hooked up properly to get the system to work. Once the under the dash stuff is all hooked up correctly you'll need to remove that valve in the engine compartment. ZMOW
 
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