There are many potential reasons why your Jeep Wrangler's heat may not be working. It could be an issue with the heater core, the thermostat, the water pump, or even a clogged radiator. If you're not sure where to start troubleshooting, here are a few tips that may help. First, check to see if there is any coolant in the radiator. If there isn't, then you'll need to add some before proceeding. Next, bleed the air out of the cooling system by opening the bleeder valve on the thermostat housing. Once that's done, check all of the hoses leading to and from the engine for leaks or blockages. If everything looks good so far, it's time to check the water pump. Make sure that it is receiving power and spinning freely. If it isn't, then replace it with a new one. Finally, if all else fails, you may have to replace your Jeep Wrangler's heater core. This is a more involved repair and will require disassembling part of your dash paneling to access it.