Probably why your hydraulics quit working was that the pump cavitated becasuse of either just way too think of hydraulic fluid or contaminents in the filter/s that are restricting it.
If you really need it to work when its real cold, run UDT fluid in the hydraulics, it's a lot lighter and moves better in cold weather.
If you really don't need it right away, just let it warm up and everything should start working again, if it doesn't then we'll look into that.
Gpreuss,
Didn't you mean access the filter on the left side?