98' Jimmy v6 Vortec Wiper problems

The black box that on the side of my windshield wiper motor assembly that the plug goes into is very loose and my wipers work when they want to. I have a hose clamp around the plug and the frame of the motor and it seems to work more than not. But still not good. I'm i going to have to replace the whole thing or does the black piece come off somehow? Sorry to be so long just trying to describe it as best as possible.

Not real sure about that.
The usual problem with part time wipers is the circuit board has a solder crack in it.
I would repair or replace the circuit board and when circuit board is out have a look inside for lose screws or what ever holds the plastic box on.
Let us know how it goes.
Good Luck

In my 97 there was a recall that was not posted anywhere for the wiper board and or motor. Have you tried taking it to the dealer to see if it falls in the recall?