When I bought the hoe, the hydraulic filter light was always on when the machine was running. After puking a bunch of oil when a seal blew on the loader, I drained the old stuff (which looked like it had some water contamination), followed the procedure in the maintenance manual to flush the system, and replaced the filter. However, the filter light still stays on. I verified that the pressure switch on the filter assembly is open / off when the machine isn't running. I checked that the light it out with the key switch on and that it does light up with the check light switch. So all seems good there. But as soon as the engine starts up, it lights up and stays lit up even after running for a while. I haven't specifically checked the oil temperature and its only been used for relatively short jaunts lately, but I'm thinking something in the filter housing assembly might be plugged up or ...? Any thoughts on where I should start looking?
Remove the filter, cut it open and look for crap in it that may be causing the problem. New filters can become contaminated quite fast sometimes.