Heater Control Panel and Blower Help Needed

[240 Tom]

Hi from a newbie,

I just bought an orange 7/71 240 out of CA from the original owner. It has 146,000 on it and has a little of the usual rust in front fenders and a few rust bubbles on the rear wheel wells, still very presentable and runs well with a pretty nice interior. The car still has all the smog equipment on it and has air conditioning that doesn’t currently work. Back in high school between 1977 and 1979 I owned 4 different Z’s, one 71, two 73’s and one 74 . Loved the cars then, and finally bought another 33 years later.

I have a couple questions that I hope someone can help with.

1.) The top heater control lever (OFF – VENT – HEAT) currently doesn’t engage anything, just swings free. I assume it’s supposed to engage, but since I never had a car with A/C I just want to make sure that the lever isn’t supposed to be disconnected when A/C is installed.

2.) If it is supposed to engage, is there a trick to getting off the Heater Control Panel? I took out the 4 screws, removed the all the plastic handles, but the faceplate doesn’t pull away, what am I missing?

3.) The blower motor also doesn’t work, I checked the fuse and it’s OK, what my next step?

~ Tom

[cbuczesk]

1. I think connects to an internal flap to direct air.

2. The cable housings are clipped onto the heater box and the actual cables are connected to flaps and the heater valve. I think there are 4 cables to disconnect.

3. Check for voltage at the fuse, switch and blower motor. You might find a wire unplugged somewhere.

Chuck

[72 OJ]

240 Tom......welcome to Z Land....Here you will find answers and tips. Good luck with your Z

[Carl Beck]

I have a couple questions that I hope someone can help with.

1.) The top heater control lever (OFF – VENT – HEAT) currently doesn’t engage anything, just swings free. I assume it’s supposed to engage, but since I never had a car with A/C I just want to make sure that the lever isn’t supposed to be disconnected when A/C is installed.

Hi Tom:

That lever is supposed to work - with or without A/C. If you look at the diagram below - there is a door or gate at #27 - that lever opens that gate to let fresh air in from the cowl for VENT or HEAT. The same lever closes that Gate at #27 for OFF.

2.) If it is supposed to engage, is there a trick to getting off the Heater Control Panel? I took out the 4 screws, removed the all the plastic handles, but the faceplate doesn’t pull away, what am I missing?

You most likely do not need to remove the heater control panel - there is a control cable that should be connected to that door/gate at #27 - - -the control lever is close to #28/#29 - - -get down there under the dash on the passenger side - and take a look.

Nonetheless to answer your quesiton - you have to unplug the Fan Switch, the radio face plate has to be out as well.

3.) The blower motor also doesn’t work, I checked the fuse and it’s OK, what my next step?

Answered above - - - and See the wires located just above and to the right of #37? Check to see if they are plugged together - and see if you have current there. There is also a fuse for the HIGH SPEED Fan that is in-line {not in the fuse panel}.. you'll want to check that as well.

Good luck...

Carl B.

[jfa.series1]

Hi Tom,

Welcome to the club. No need to remove the heater controls face plate unless you are into self-abuse! This is one of the more complex pieces and removal won't fix your problem. In fact - it has to be in place to attach the control cables to their various levers.

As Chuck said, there are four wire cables attached to the three levers. The OFF-VENT-HEAT lever has a single cable running to a lever on the top right side of the plenum box behind the blower motor. It controls the outside air into the car. The TEMP lever also has a cable to this same general area - it attaches to the water valve near the firewall. The cable you are having trouble with may be difficult to reattach with the blower motor and A/C components all in place. Get into the passenger side footwell with a bright flashlight and trace the two wire cables. Removal of the passenger seat may give you extra room to maneuver.

Jim

Good luck with your new find and Enjoy The Ride!

Edited May 13, 2012 by jfa.series1

[Carl Beck]

The TEMP lever also has a cable to this same general area - it attaches to the water valve near the firewall.

The water control valve would be item #6 in the diagram above. AND YES - they will all be harder to get to with the Dealer Air installed.

FWIW,

Carl B.

[ironhelix]

I recommend removing the seat, too, if you plan to spend much time under there. I installed AC in my z and the control cables did not have to be changed. If the blower motor has died, I recommend upgrading to a honda blower motor. Got mine for cheap from Pick 'n Pull. Made a big difference.

[240 Tom]

Thanks for the warm welcome and all the help...

After determining that the 3 cables that I could find were all attached, I moved on to removing the Heater Control Panel...loads of fun.

I removed the 3 cables I could find at their termination point, and the one remaining directly off the back of lever. Turns out the reason the lever wasn't working was because a pin and c-clip had popped off. The top lever that was not working controls two cables, one to the drivers side that operates the vent door, and the other that leads somewhere around the blower housing. After lubricating the 3 cables everything else and getting it back together I think I found the reason why it broke. The 4th cable that routs somewhere behind the blower housing (the one I couldn't find) is seized, someone probably tried forcing the lever causing it to break.

Sooo...does anyone know what I need to do to get to the end of the cable that routs behind the heater housing? Will removing the 10 or so screws that seem to hold the two halves of the housing together get me there? At this point I don't know if its the cable or whatever lever the cable operates that is seized.

Also, any help as to the whereabouts of the inline blower fuse would be most appreciated.

Thanks again.

~ Tom

[Walter Moore]

The mystery cable operates the door that directs air from either the outside into the dash vents, or from the inside into the heater box. This mechanism is in between the fan housing and the firewall. It is relatively easy to get to if the dealer installed air conditioning evaporator box is removed, but with that in place I suspect it is very difficult. (My evaporator box is stacked in the corner of the garage somewhere...)

The top lever on the heater control panel is fairly difficult to move under the best of circumstances. If the cable seized, or even just got kinked I can see where someone might break something before realizing that it was stuck.

[EScanlon]

I'm reposting from this thread, post #7:

http://www.classiczcars.com/forums/thread33258.html

Take note that there are FOUR cables and THREE levers. One of the levers actuates TWO cables and that is the TOP lever. The other two levers control single cables.

The top lever controls:

a) the fresh air vent that opens at the firewall vent valve behind the heater blower motor (the longest cable)

AND

the internal flap valve that ducts the air through the heater core OR straight through to the side and center vents in the dash. (the cable connected to the uppermost connection on the heater box on the left side)

(FYI: There is NO position for the heat to flow out of the side and center vents, you will only get fresh air ... or not.)

The middle lever controls the hot water valve. (right side of heater)

The bottom lever controls the two side doors on the heater box (left lower side of heater box). When the doors are shut the air is forced through to the defroster ducts, otherwise the air is allowed out to the "room".

FWIW

E

[Carl Beck]

Good discription E.

I'm reposting from this thread, post #7:

http://www.classiczcars.com/forums/thread33258.html

Take note that there are FOUR cables

Item #60,61,62, & 63 in the diagram previously Posted above.

...and THREE levers. One of the levers actuates TWO cables and that is the TOP lever. The other two levers control single cables.

The top lever controls:

a) the fresh air vent that opens at the firewall vent valve behind the heater blower motor (the longest cable)

That would be Item #28 in the diagram previously Posted above.

AND

the internal flap valve that ducts the air through the heater core OR straight through to the side and center vents in the dash. (the cable connected to the uppermost connection on the heater box on the left side)

(FYI: There is NO position for the heat to flow out of the side and center vents, you will only get fresh air ... or not.)

That would be Item #15 in the diagram previously Posted above.

The middle lever controls the hot water valve. (right side of heater)

That would be Item #6 in the diagram previously Posted above.

The bottom lever controls the two side doors on the heater box (left lower side of heater box). When the doors are shut the air is forced through to the defroster ducts, otherwise the air is allowed out to the "room".

Not shown in the above diagram.

FWIW,

Carl B.

[GreenZZZ]

Its good to see photos of the guts of the HV system. http://www.classiczcars.com/forums/thread23409.html

One problem that is good to check is a blown coolant hose or leaky heater core or "water ****" getting coolant on the bottom heater flap hinges and fusing them in place with rust. When it gets rusted shut, a driver will try to force it and the cable will overcome the locking screw resistance and the cable will come free so it could be two problems.

Edited May 15, 2012 by GreenZZZ
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