Working on a friends car (1973 240-Z) and trying to figure out why we can not get the heater fan to run with the OEM switch. The fan has not worked for about three years. A year ago he took the fan out and wired it direct to the battery to test it and it ran fine. That led him to assume the switch was the culprit. I had an extra switch, which we tried with no success. I'm wondering if there is anything between the fan and the switch that we may be missing. Of course both fan switches could be bad but the odds are at least one would be working. Is there an easy way to verify the switch is good? Any other thoughts regarding things to check.

Check the IN-LINE fuse for the fan.

Next, check that the internal voltage drop resistor in the outlet side of the fan is still connected, if it isn't the power doesn't get to the motor from the switch.

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