My 1999 Jeep Grand Cherokee with the 4.7L V8 has been running a little hot recently. The check engine light is on with the code P1491 which indicates the Radiator Fan Relay Circuit but the cooling fan still seems to be working. I'm having trouble figuring out what the issue could be. Also I am slightly leaking radiator fluid but I keep my reservoir full.

After checking the obvious things, bare in mind that some of these 4.7 engines use a water pump with plastic impellors which crumble and can no long circulate coolant. Also consider that the sending unit or guage is wrong. Coolant level low. Thermostat not opening enough. Clogged radiator inside and blockages outside. Don't let this particular engine overheat a whole lot because aluminum heads on a cast iron block are sensitive to heat....aluminum expands three times more that cast iron and is weaker. I hope you have good luck.

Thank you! I’ll check it out after work and let you know what I find

I had another idea. Keeping the reservoir bottle full is good. But it refills the radiator >only< when things cool down over night parked. So also check the radiator directly for fullness when warm. But you know to be careful uncapping a warm/hot radiator. And take another look why you are getting a code P1941. It might be an intermittent electrical problem and they are the worst kind.