As one of the "while I'm in here, might as well do this too" type of jobs to be done when I was replacing the gas tank, I removed my heater fan box to investigate why the heater/defroster fan never worked since we bought this car in 2016. It's a model year 1970 that was built in December 1969 according to the door jamb sticker.

The heater fan box was completely filled up with leaves and debris. These early cars did not have a screen used under the air intake louvers. The fan motor couldn't turn at all with all the leaves, twigs, and dirt built up in the heater plenum and vent outlets. No wonder the motor had burned out. Here is a photo for your viewing enjoyment showing what I discovered upon separating the fan from the heater box housing:


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You can't smoke any of that. What a joke.

That is such a great pic.....

Unfortunately this is not too uncommon.

Never park under a tree?

Imagine what the innards of some us old guys looks like??

This is SOOOOOO 914....

Looks like it was working fine, for a while.

I have a blower from a 1970 that works fine.
$20 plus shipping Medium Flat rate
Total $36
@Pezz
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My photo is of the heater fan blower under the cowl; not the one in the engine compartment!

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Wrong fan. Yours is an engine bay fan. His is the fresh air fan in the front trunk.

@Pezz

Pulling out the gas tank is not a simple procedure for inspection. Anyone know from what model year onward screens were put on to prevent this?

According to the 914 Restorer's Guide the cowl intake screen was added in June 1973.

I wonder how much debris is in the fan on my 76 which does have an intake screen?

I had a 92 Nissan pickup and small oak leaves would get into the ventilation fan and sometimes get stuck in a position that would allow them to paddle the centrifugal fan blades. Sort of like cardboard paddles on bicycle wheel spokes. Annoying. Luckily the fan could be accessed from under the dash fairly easily.

I had to pull out the gas tank to replace it with a new tank. Taking out the heater fan box was just one of those "while I am in here" ideas. Glad I took the heater fan box out and discovered all the leaves and debris inside the fan housing. It certainly explains why the fan never worked. The fan would not even turn. It also explains the melted/shorted out wires in the heater fan harness.

One more 'while you're in there' awaits.
Check the sliding contacts on your dashboard heat/defrost controls.
Another sight to behold most likely.

+1 on the brass contacts on the slider lever assy. I just went through the same "discovery" and the high speed contact melted the plastic below it and it sank down slightly so that the moving contact couldn't touch it because of mushroomed melted plastic around the edges. A little surgery with Xacto did the trick.

BTW, advice I got here steered me to PartsGeek for the replacement motor/fan assy. By far the lowest price and it fit perfectly.

Tip for getting the box back in - use a step drill to slightly enlarge the holes that the two mounting bolts go through. And get a helper with a piece of 1x2 wood to use as a lever pushing the box up and back toward the firewall while you insert the screws.

Good luck,

Ron

One more 'while you're in there' awaits.
Check the sliding contacts on your dashboard heat/defrost controls.
Another sight to behold most likely.
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Yes, that’s on my list now. But that will have to wait until after the Werks Reunion in Monterey. I need to get the new gas tank and steel fuel lines installed and the body vinyl wrapped by August 15th.

Not to be a nit picker, but isn't the fan in the front the fresh air fan, not the heater fan? I thought the one in the engine bay was the heater fan? I only point this out because i'm trying to troubleshoot why both are not working and i do seem to find they are referred to interchangeably and it makes it fun trying to do research. But i could also be wrong.

I have a 70 and when I went to put that back in I put the 914rubber screen in to avoid the crap that collects in there.