power window problem (intermittent)

2002 Ranger XLT- Occasionally, when I push the driver window down switch, I hear a chatter/buzz under the dash and the window doesn't open. If I release the switch and then push it again the window opens normally.
Is a relay sticking? ...and needing replacement?

sounds like a good guess

Figured out the cause of the problem.
It was just a dry (sticking) window mechanism.
The actuator arm wasn't sliding in the track smoothly and was binding.
Didn't have any silicone grease so I used Vaseline!
Works fine now!

I initially thought I had a bad relay. I swapped the relays for the driver's window and passenger window but that didn't change anything. By the way, the relay box is located under the dash. It is to the left of the steering shaft (as seen laying on the floorboard and looking up). There is a cover over the relay box. The lowest relay is for the driver's window. Above it are two more identical relays. One is for the passenger window and the other is for the interior light. I forget which is which. There are also two other larger relays(?) under that cover but I didn't remove them so I'm not sure what they are for.

As Droopy would say, "I'm happy!"