No heat from heater after replacing water pump

Have you bled the cooling system completely? If there are air bubbles in the cooling system, that will keep your heat from working. Also, if memory serves, these trucks have an issue with the heater cores easily getting clogged up, and then not allowing much, if any coolant to go through. It could be a coincidence that it got too clogged up at the same time that you had to replace the pump.

To clean out the heater core, disconnect the heater core hoses from the engine, while leaving them connected to the core. Point one of them where water coming out wouldn't get on any important electrical components, and hook your water hose up to the other one. You might have to be a little creative to get the water hose connected to heater core hose, but it's doable. Then, turn your water hose on with just low pressure to start with. If nothing comes out of the core after about ten seconds, turn it up a bit and wait. Eventually, if the core is clogged, you'll see mud and crud start coming out. Then water will start flowing out. Let the water run for three to five minutes so it completely cleans out the core.

Now to bleed the cooling system, turn off the water hose and put everything back together. Take your radiator cap off and fill the radiator with coolant. Start the engine, with the heat cranked all the way up, and let it idle until the engine warms up a bit. Watch the coolant level in the radiator. When it dips down, pour more coolant in the radiator immediately. Do this for a while until the coolant level stops dipping down. Turn the engine off and put the radiator cap back on. It's as simple as that.

Start there and let me know how that goes. We'll go from there if more troubleshooting is needed.

Hi,

I noticed it has been a couple of days since we heard from you. Have you been able to get the heat working? We're interested in knowing.

Take care,

Joe