All, did several searches both here and consulting the oracle (google) but haven't come up with any ideas...

My '93 Accord had the typical fan blower motor and resistor issues a few months ago so I replaced both. Everything has been hunky dory until this afternoon. As soon as I turned the car on a horrible noise emanated from the blower motor vicinity and persisted even if the fan switch was off. The pitch changed slightly depending on fan speed but was constant and loud, about the pitch of a lawn mower. The noise happens when the key is on accessory, start, and run. No noise when key is in the off position.

Removed the blower fuse, noise still happens. Also tried removing the radio fuse, but the noise still happens. I'm officially stumped.

I don't think it could be the fan blower but the sound is coming from right there. It's not engine related because the noise happens with the engine off (key on accessory).

This weekend I'll tear into the HVAC area and isolate the source, but any suggestions are greatly appreciated.

 

The only thing that would make noise is the blower motor. If you have a volt meter, unplug the connector to the blower. One wire will have 12V to ground. The other wire should be open to ground (infinite resistance) to ground when the fan switch is off. If you have ground then you will have to work backwards to the resistor, then the fan switch.

 

A follow-up to the original post with information on what fixed the problem:

Of the 3 connectors to the blower assembly, the gray connector closest to the front of the car was disconnected and the noise went away. It is a 3-wire connector. I believe it goes to the servos which open and close the vent flaps. The blower fan works at all speeds and off/on so it's definitely not a faulty blower motor.