1971 240Z Heater Controls

[suleymantezgul]

I am trying to put my heater control in order and I have not been able to locate another 240-280z in Turkey for reference .

I need to know what all the three controls do,so I can install the cables at their correct locations.

[EScanlon]

The top lever, AIR, operates TWO levers.

The middle lever, TEMP and the bottom one, DEF, operate one lever each.

The AIR connects to the Fresh Air Vent Flapper Valve at the firewall to allow or not allow the entrance of fresh air. This is the longest of the 4 cables. The attachment point should be behind the fan and on a LHD car to the RIGHT of the valve. ( I don't know if on a RHD car the Fresh Air Valve would be reversed, but I doubt it.)

AIR also connects to the Heater Box Plenum to actuate the diverter flap that sends the fresh air either to the heater core or to the vents. This is on the upper right side of the plenum.

TEMP connects to the Heater Valve on the right of the plenum. It regulates the amount of water going to the heater core.

DEF connects to the lever on the left hand side of the plenum and actuates

the doors on the bottom of the plenum that open to allow the heated air to escape.

Note, FRESH COLD air is the only air you'll get out of the Center Console Vent and the "Eyeball" vents on either side of the dash. When the controls are placed on HEAT the air is diverted to either the Defrost tubes just below the windshield or to the floor, depending on whether you have Defrost or Room selected.

That's it, hope it helps.

By the way, if you haven't already done so, add a drop of light mineral oil to the wires inside the housing and operate them several times to lubricate the inside of the wire housing. Also check to make sure that the internal flapper valves of the heater box are not frayed or unglued.

Enrique Scanlon

[240znz]

That explains why my Zed was freezing when I drove it home some 500 miles. No matter what I did to the heater controls, I was only getting cold air out of the centre vent and side eyeballs. The controls are completely rock solid anyway, so I couldn't select room.

Would selecting "room" stop fresh air from coming out these 3 vents?

Any tricks to rebuilding the entire heater system?

[EScanlon]

The ROOM / DEF lever ONLY has a function when the AIR lever is set to HEAT.

To stop the fresh air from coming through the center and side vents you have to close the fresh air flapper valve by selecting OFF.

The system is real basic, the only thing to know before refurbishing it is that the flapper valves and the heater core are outfitted with gasketing to make a tight seal and ensure air flow through the system.

Hope this helps

Enrique

[MikeW]

AIR also connects to the Heater Box Plenum to actuate the diverter flap that sends the fresh air either to the heater core or to the vents. This is on the upper right side of the plenum.

I was just in the middle of trying to get my cables hooked back up properly and found this post. As always thanks for the useful information. I do note that, at least on my car, the diverter flap control mentioned above is actually on the upper left side.

[suleymantezgul]

Mike,

Thank you for your info. about heater controls.My heater is working properly thanks to you.

[MikeW]

Mike,

Thank you for your info. about heater controls.My heater is working properly thanks to you.

I suspect you meant to thank Enrique (EScanlon) as his post was helpful to me as well.

[suleymantezgul]

Yes,many thanks to Enrique for this very helpful explanation.

[280z]

question for enrique, or anyone who could answer it. ive been ripping apart my car trying to find out why the air flow is so low coming from my vents. i was playing with the controls and realized that the air flap never send all the air to the AC. it either sends it all down to the heater when set at "fresh", "rec" or "def" or the flap stops half way when set at "a/c", "bi level" or "fresh". is this the problem? isnt the flap supposed to send all the air to the air condition if set at "a/c" or "vent"?

[sblake01]

question for enrique, or anyone who could answer it. ive been ripping apart my car trying to find out why the air flow is so low coming from my vents. i was playing with the controls and realized that the air flap never send all the air to the AC. it either sends it all down to the heater when set at "fresh", "rec" or "def" or the flap stops half way when set at "a/c", "bi level" or "fresh". is this the problem? isnt the flap supposed to send all the air to the air condition if set at "a/c" or "vent"?

One of the plastic levers in your control panel has come unhooked from the cable or broken more likely. I went through this on my 78 a couple of years ago. You'll have to replace that whole panel. It's easier than replacing the broken part. I got mine at the junkyard. There are two different ones. One for AC and one for non AC.

[280z]

One of the plastic levers in your control panel has come unhooked from the cable or broken more likely. I went through this on my 78 a couple of years ago. You'll have to replace that whole panel. It's easier than replacing the broken part. I got mine at the junkyard. There are two different ones. One for AC and one for non AC.

thanks you for your help, ill go check it out now!

marc

[280z]

my car now blows cold hard air! thanks everyone for your help!!