New issue with the 73 220d.

When blower fan is off hot air will come out provided the car is in motion.

When the blower fan is turned on the heat goes away. Blows cool air.

Just sitting at a stop with the engine running there is no heat coming from the vents with blower fan off or on.

Could heater core be blocked?

Check the inlet and outlet temperatures of the heater core after the motor is warmed up. They should both be about the same temp if the heater core is not plugged up. Don't forget to make sure the monovalve and the heat control levers on the dash are set properly.

I am currently working on a '73 220D also and have found so far that I cannot get the heater blower to engage at all. I am not 100% sure of the cause of this yet.

There are two blower motors, one for a/c and one for heat. The a/c one is low in the console and the other is higher up in the dash.

As I understand it, (perhaps someone more educated than I will chime in here) the temperature control knob activates one system as opposed to another. If you turn the knob all the way counter clockwise, it should engage the heater blower. The other direction, the a/c. There is a vacuum control on the switch that works the door actuators on the left and right sides of the heater case which will also switch between heat and a/c.

One of these actuators on the passenger side on my vehicle is bad and leaks. So I assume that is why mine won't work.

I will be in touch with the dealer in the next week or so to see if it is still available so I can continue diagnosing the problem.

I hope that this at least helps you to rule out some of your problem to continue forward.

Rick

Vacuum elements as the stealership calls them ar $180. each. They were so kind as to offer a discount on them. $140. each is so much better.

Did some looking on eBay and made an offer on two that was accepted for $100. I believe I can swap the rubber diaphragms out and rebuild my bad one. I hope!

We'll see when they arrive.

Any new news on your problem jgumina?

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1973 220D 78k

Yes, sold the car. It was originally my son's vehicle, but he tired of it quickly. Just wants to get in and drive, not do any maintenance, etc. He bought a Ford with auto tranny and power steering!

Too bad. I wouldn't have minded a second 220D.

Have a good one!

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1973 220D 78k