is there a video on Youtube to show me how to replace the rear wiper motor on my 2005 grand caravan

I'm sure you could search for one on YT. Most of the ones I've ever worked are accessible by removing the rear door panel, there's really not a lot to it. I'd try to grease the old one first though, use white lithium grease or spray lube. Rear hatches are notorious for collecting moisture and the old one may just need a good lubing. (Once you have the door panel off you should also lube the latch too.) PS: shop around on prices, rear wiper motor prices are all over the map.

I tried spaying it a while ago (just on the outside not taking the rear door panel off) around the wiper post but this dis not do anything. I fear it will need to be replaced fully.