76CutlassSalon

If so, then how? This would be on our '76 Cutlass Salon coupe with factory A/C. I do have the factory service manual including wiring diagrams, so that will help.

If there exists no way to do it without disabling something more important (or without re-engineering the entire wiring system) then no biggie; it's just uncomfortable in the winter (while the engine is still cold) and a battery drain when working on the car with the ignition switch in the "on" position.

Jeff

MDchanic

If you mean, can you turn the fan off, in general, the fan is off when the main selector is in the OFF position, though I will admit I have never had a '76, so I cannot swear to this for that particular year.

- Eric

rustyroger

Simply turn the A/C to "economy" mode and set it to "defrost". That will stop you having air blowing anywhere but to the windshield while the engine warms up. I believe the fan is always on when the ignition is on, certainly this was the case on my '78 and '79 B bodies.
You can simply remove the relevant fuse or disconnect the wire to the fan or resistor pack if you don't want it running while you are doing other work.

Roger.

76CutlassSalon

Thanks, Eric and Roger.

I supposed that this might require some disconnection of wiring; I don't have an "Economy" setting, but I will certainly look into the fuse-removal idea --- so long as doing so won't disable something else.

Jeff

oldcutlass

You can always put the fan on a toggle switch and manually turn it off. Just a note, leaving the ignition switch in the on position for a long period of time is not a good idea with engine not running.

jaunty75

Unfortunately, no. The "flow-through" ventilation system meant that the fan operated at low speed whenever the ignition was in the ON position. There is no way to turn off the fan with any switches. The whole point of this was to keep outside air constantly moving through the car. The heater and A/C could be turned off by moving that lever to the OFF position, but the fan continued to run.

I think that only option for the OP if he wants to be able to leave the key in the ON position and not run down the battery is to find the fuse for the fan and remove it.

MDchanic

On earlier cars than this '76, the "Flow-Through" system turned off when the big slider was set to "OFF."

Also, on Olds cars (but not all other Divisions), there was a thermostatic switch that disabled the lowest fan speed when the slider was in any other position than OFF and the temperature was below 40 degrees.

- Eric

jaunty75

No, it didn't. I have a '73 Olds owner's manual.

On page 26 under "Ventilation System." "Another feature of the system is continuous low-speed operation of the heater and air-conditioner blower resulting in an uninterrupted supply of outside air whenever the ignition switch is on."

The A/C and heater systems themselves could be turned off, but the fan could not be, and this is the OP's concern.

MDchanic

Okay. I just checked a couple of CSMs.

Apparently, on the fullsize cars, going back at least to 1970, the fan works as you described, but in the A-bodies as late as 1972, it works as I described.

I did not check the A-bodies after 1972.

So, the operation of the system is different in different models in the same year.

- Eric

76CutlassSalon

Okay, thanks guys. I guess what I was looking for (and failed to make clear) is which connector (wherever it might be) I could disconnect and halt the FTV without impeding the regular function of the HVAC system. I guess it just doesn't exist.

Jeff

jaunty75

Cool.


From the '76 Olds brochure. Note the last paragraph in the first column on the right side describing the "flo-thru" ventilation system. A little hard to read, but if you click on the image, it gets bigger.

MDchanic

You have to put a toggle switch in the power supply that goes to the HVAC controller on the dash.

It's brown on the older cars - not sure about '76.

- Eric

76CutlassSalon

Thanks , Eric.

Thanks, jaunty; I like the brochure excerpt.

Jeff