Hi there,
I have a 1959 98 Olds Holiday Sceni-coupe.


When I turn the ignition on the fan runs even when it is in the 'OFF' position. I have removed the fuse until I received my N.O.S heater control resistor. Put that in tonight and still have the same problem.


Has anyone come across this before or know why the heater fan remains on?


Any help appreciated.


Thanks


John.

 

Hey John, My 76 does the same I have heard that some of the cutlass years were made to do this during the time when they wanted to try the cabin air circulation. I just unplug my heater motor and plug it in when I need it. This was what I read on the other olds site as a visitor. I'm not sure if it was back as far as your year of olds.

 

Thanks for the info there.
Mine used to work correctly. (Switch on and off when I moved the lever), but now for some reason it has stopped working correctly. Like yourself, I have unpluged the fuse. Its been a hot summer here so its been disconnected for a while now.

I have no idea why it stopped working all of a sudden.

Perhaps the heater sensing unit may need replacing now.

 

Are there anymore ideas out there?

Thanks

 

In my 66 big cars, they used the same 3 position switch for a/c and non-a/c cars. The power wire to the unit (heavy gauge brown, in 66) is supposed to be plugged in to the outer spade at the back of the vacuum unit, not the lowest spade on the 3 postion electrical switch.

Just as a test I tried connecting power to the 4th spade of the 3 position switch and it powered the unit even when it was supposed to be off.

Lesson here is route power to the vacuum unit, electricity goes from it to the hi-med-low switch

 

Do you have ac on your car John? Does it run with the ignition on and the motor not running? That is to say, if it runs without vacuum then the vacuum controlled master switch is probably stuck closed. If you have ac I'm not sure how it works. I believe the off position on the controls only switches the vacuum to the thermostat and the diaphragms that control the defrost and master switch. The wiring diagram in the service manual shows this. I can try and post the schematic if you don't have one. Since I'm seeing this a month late you probably already solved it!

 

Hi there John.
Thanks but not solved as yet. Still trying though.


There is no A/C on this car.


There is a diagram of the layout in my manual, a type of wiring diagram but I think it is incomplete or only a partial.


Any more info greatly appreciated.


Thanks


John.

 

John,

The fan is controlled by the 'Off' push button. Behind it is a long switch. Check the contacts are releasing. If not the fan will stay on.

Good luck Scott

 

I think this is a pic of one

 

Lazy, does your car have ac? Mine does not and the switch you refer to is not on my car. Down Under, on mine, the temp lever sets the gap for the vacuum valve to the heater thermostat which is basically a valve that is temp sensitive. When the push buttons are not in the off position and the temp lever/thermostat is calling for heat, the vacuum passes through the thermostat valve, activates the vac controlled valve allowing hot water into the heater core. The master switch diaphragm on top of the heater inlet in the engine compartment which closes the master on/off blower control switch is controlled by both the ventilation and heater controls. The vacuum diagram is shown in figure 16-22 of the service manual on page 16-13 for non ac cars. The heater wiring is shown in figure 16-24 on page 16-15. There is a nice chart on page 16-12 of the manual that shows what happens when the push buttons are in various positions. The key question in my foggy mind is does the blower run when the ignition is turned on but the motor is not running. If it does, that sounds like an electrical problem related to the master on off switch on the heater case in the engine compartment or the diaphragm that controls it. If the blower motor runs when the engine is running but regardless of the push button positions, that sounds like a problem in the vacuum control circuits. So, to test this, if the summer vent and heater controls are both off and with the engine running, if the blower is running, disconnect the vacuum line from the diaphragm heater inlet next to the master on/off switch. If the blowers shuts off it is a vacuum circuit problem. If the blower continues to run, that means the master switch is not opening and may be a faulty switch or the deflector inside the inlet box is crudded up and not letting the mechanism spring back to open the switch or that diaphragm is screwed up which is less likely.

Now the disclaimer. I just finished rebuilding my entire heater system and tested it and it worked. But since I'm still putting the car back together, I have little to no actual experience using it. Much of what I said here I learned from the diagrams. I bench tested everything and it seems to work as it should. I DO KNOW that ac and non-ac cars are different. Hope this didn't confuse the issue further. Let me know what happens if you do the tests I described.
John

 

Does yours look like this ? Excuse the crappy shot.
Yes mine has AC.

 

the pic of the heater control

 

Could it be a vacuum issue maybe relay?

 

That looks like my heater control Lazy. Two position switch, low and high but it's much smaller than the one you showed in an earlier pic.

 

The pic is a switch that mounts behind the control panel. it has contacts on it which turn the power on / off when one of the other buttons are depressed ( Direct, indirect and defrost).

Scott

 

Interesting Lazy. Mine doesn't have that switch. Power to the blower gets turned on by the vac diaphragm when the buttons get pushed.

 

If the blowers shuts off it is a vacuum circuit problem. If the blower continues to run, that means the master switch is not opening and may be a faulty switch or the deflector inside the inlet box is crudded up and not letting the mechanism spring back to open the switch or that diaphragm is screwed up which is less likely.

Hi John,

The "deflector".? Is this inside the box that houses the heater core on the passenger side?

Thanks

John.

 

Had to refresh myself on this a bit. If the blower runs when the motor is running regardless of position of buttons, I believe that means the master control switch on top of the heater inlet box (passenger side inside engine compartment) is staying on. This is a vacuum controlled switch. And yes the deflector is inside this box. The heater core is actually in the box inside the passenger compartment. The heater inlet box is on the other side of the firewall in the engine compartment. You can remove the box by removing the six nuts and the rubber boot which connects the box to the blower housing. But you can check it out pretty well just by observing what happens when the motor is started (providing vacuum) or by watching when someone presses the buttons when the engine is running. You can also disconnect the wires to the switch (blower will shut off). You can check the operation of the switch with an ohm meter provided you have the wires disconnected with the engine both running and off. Finally I should mention that the mechanical connection between the diaphragm and the switch is adjustable. Maybe an easy fix if out of adjustment. Hope this helps some.