Help diagnose inoperable S3 heater blower motor

[toggle45]

I've direct-connected ground and hot leads to car battery measuring 12.5V, but motor lifeless. Rheostat measures 2.4 ohm end-to-end, so assume no open circuit there. The motor hasn't run for nearly 50 years, but has not been exposed to water, looks new, and shaft turns freely. Don't want to take it apart if there is something else I should try first.

Anyone have one go bad and figure out the fix?

[lotusfan]

Hi Weldon

If you put heater blower motor into the search feature you will get some suggestions. However, if yours is as low mileage and shiny like you say it is unlikely to be worn out brushes. It may be either a brush or both of them stuck in the holder or it might be corrosion on the commutator.

If you don't want to dismantle it and it is out of the car you could try tapping it firmly with a soft mallet to try and jar the brushes free, if they are stuck.

You say it turns freely, can you feel the brushes scraping on the comm or it it really free? If you can feel the brushes scraping you could rotate by hand a few turns and see if it cleans the comm.

You may have to bite the bullet and dismantle, it's not that hard and if it is such good shape as you say it should come apart easily. Remove the 2 through bolts and remove the end where the wires come out. Do not use force.

Report back and good luck.