Electric Awing won't close

You need to check the motor and connections to make sure you've got a good connection. Most of the power awnings don't have well protected motors and/or connections. Best way to check would be to hook up a battery directly to the motor and see how it operates. If it's still slow, time for a motor replacement. But if it works fine, then check connections, switches, and wiring in general.

I had to replace the motor on my power awning, it was doing the same thing as yours. I got a new motor off Ebay, and it was about half the cost of one from an RV vendor.