How may I bench test the blower motor found in the first two generations of Muranos, as well as other Nissans and Infinitis? This blower motor has a three wire interface. In addition to ground and +12VDC, there is a third connection for speed control. There is no blower motor resistor. Speed control is accomplished by a low voltage, direct current, square wave input. The duration of the pulses determines the speed.

I think, a signal generator would work. However, besides not having one, there is the issue of impedance matching. The signal generator, the blower motor, or both could be damaged.

I'm hoping, there is a simple procedure or tool to bench test this motor.

Any help, or advice would be greatly appreciated.

Are you sure about ground and 12v dc? You could be right. Have you seen brushless motors? Those utilize three wire configurations, but not quite like you describe. I think they're all swapping between hot and ground and innate. You'd need and ESC for brushless motors to power it.

The more I think about it, the more it sounds like you read that information and it's probably correct. So ignore the stuff about brushless. If you have a bunch of these motors to test, perhaps getting the actual control units from a parts car and running power to that will enable your bench testing.

You could always simply use the 12v and ground to see if it works. It will either run full speed or not at all. The second case meaning it needs the PWM input to work. That in turn means there is a control chip inside fan or on the outside of it and you may need to disassemble further (if possible) to get to the true 12v and ground inputs which will be after the chip control there. Of course if they glue the whole thing up in epoxy you're out of luck there.

CentralCoaster33, my information regarding the blower motor is from the FSM: Heating & Airconditioning Control System. The following video goes over the three types of common blower motor configurations:

https://m.youtube.com/watch?v=QmSp5nmIkXM

The second type, discussed in the video, is the one in the Murano; third type is the one you related.

I could get another control unit. However, than I would need to figure out its inputs, or just swap it in. Parts swapping electrical and electronic parts has its pitfalls, particularly when the part are expensive.

Regardless, your response is appreciated.

Amc49, the device I call a blower motor is an integrated DC motor with a chip that requires PWM input. My objective is not to determine where a failure is within this assembly, if any, rather, it is to test the entire assembly. What I am lacking is away to provide PWM input to the assembly.

Regardlesss, thank you for your input.

That's the kicker of course, you don't just find PWM test equipment growing on trees. What the OEM goes to more and more to force in more dealer work. I myself have looked for the same (for alternators) but no results so far.

When I was in parts I found that even the expensive alt testers do not range the full range of possibility that PWM can go, typically the machine only tested at one certain frequency point to determine good or bad and kind of shoddy I thought. And why even bench testing could not show all of the issues the alternators could have.