My heater motor doesn't blow air at all when I turn the heater switch on. I checked the fuse box and they are all OK. The connections at the blower are OK.

What else may I look at?

There is a trick to that pesky blower motor.

It has a separate inline fuse under the dash by the console area.

It is on the end of the Red wire coming from the fan speed switch, whereas the rest of the switch wires head off to the blower motor.

Chances are that little sucker has blown:nervous:

He normally gets his power from the normal fuse box via a 20A AC fuse.

On a '72, depending on whether it has A/C or not, that inline fuse may be 30A or a lesser rating.

Check what the rating is on the old one and replace it with the same rating, but certainly NOT greater than 30A:finger:

P.S.

Try all the fan switch settings.

There is a dropping resistor in the housing that is switched out when you go to HIGH speed but reduces the voltage when on the other settings.

It might be fried!

There is an accessory relay on the right side that controls power to the blower motor and rear window defogger. I know it is not drawn that way on the wire schematics, but, I have not found a 240 that was wired (with the defogger) different.

there is a fuse holder ( modern two pin type ) in between the A/C compressor and the fuse box. It is a red wire.

This one just seems to give power to the A/C compressor and is coming from the 20A fuse in the fuse box ( A/C Air ).

Is there another fuse that could be under the console and do I have to remove the console to check or is it under the dashboard or on top of the glove box?

I can see an " online " fuse on the wiring diagram but I cannot locate where it is.

I can't remember exactly where it is, that is why I suggested physically tracing the "hot" [Red] wire from the fan speed switch:ermm:

Just a thought , when you check the fuses use a multi meter. So many times the fuses look good when there not. Gary

There not just one but TWO fuse holders to this S""T and both were blown.

The car is fully original and both fuse holders have 20 amps. The console and glove box have to be removed to work properly, at least on mine because they were hidden under the original radio.

Now, everything is OK but my blower motor (Honda) is not as strong on the third speed (which is supposed to be close to double the original Nissan) and my A/C will not blow as it is supposed to be with the Honda motor.

I disconnected the wires at the blower motor and I am not sure if it may be not the problem. These fuse holders are so hard to reach that I don't want to have to change them again.

The Honda motor has a + and a - black electrical connection.

Which one of each of my wires go in?

Is it possible that I just inverted the wires and the motor is not performing at the full speed it was doing before?

If the wiring is reversed to the fan motor, the blower efficiency will be terrible:rolleyes:

The fan is what is called a tangential or squirrel cage design.

To pump air it definately needs to rotate in the correct direction.

The Z wiring feeds +12V from the supply fuse on the Red wire, that should go to the + wire of the blower motor.

Obviously, the other wire is - and should be earthed.

You should be able to tell which direction the motor needs to rotate by feeling the efficiency of the air flow.

If you want, you can extend the wiring on those fuse holders so they are more easily accessed in future, and convert them to conventional blade type fuses.

I won't tell anyone

No prize for having to dissemble the interior just to replace a fuse:eek:

Thanks, you were right. The wires were inverted.

I have a 72 240Z which needs a stronger and more vibrant fan motor for after market A/C , heat and defrost. People suggested a Honda Civic or CRX, but which setup and year do I need?