TRANE Air Handler problems
 

The fan motor only works when the cover panel is removed... not sure what the issue is. The motor sounds weak when it starts up, could it possibly be a relay? I honestly have no idea. It's a 1985 TRANE model. I would appreciate any input. thank you

With the limited data you offer I will guess maybe a bad capacitor?

Relay probably wouldn't work with the panel off any better then it would with the panel on.

Check capacitor as said above.

changed the capacitor, still having the same issues... When i remove the cover that accesses the fan and then turn on the air handler it works. So then i replace the cover and it continues to work until the next time the air handler kicks on and tries to heat the upstairs... it sounds like a noise is coming from the fan motor area... it's an annoying buzzing/humming sound with some crackling noises.... do i need to change the fan motor?

also, i had the capacitor checked and it was a little weak so that's why i changed it...

Sounds like a wire is being moved or pinched when you close the panel.

Burned contacts on an old relay can give good and bad connections intermittently. Plus you may also want to rule out contact with wiring or blower when closing the unit.