There is no heat from the heater, is it a thermostat problem or a rad problem?

Is both heater hoses hot? Could need radiator and heater core flush. Water pump propellers could be detoriated. I have seen this on vehicles before. Just some ideas to look at.

make sure you installed the themostat the right way and that it has the proper heat range for your vechicule.normally after installing a thermostat,you remve the rad cap and fill the radiator with antifreeze,then srart the car and wait till the themostat opens and prestone level falls.refill rad and put rad cap back on.turn on heater and you should have heat,if not have your rad cap tested to make sure it is holding the proper pressure.your antifreeze mixture should be 50\50.

maybe the tap for allowing the water into the heater rad is not opening or the heater rad is blocked check the two hoses coming from the heater rad and see if they both feel the same heat when the engine is hot

Good place to start is a cooling system flush and thermostat replaced.

Start the engine when cool, remove rad cap and start engine and let it run with the heater on. (not defrost) Top up coolant as needed in rad, and let it run until either the rad fan comes on and off 2 or 3 times, or you can see increased flow in rad from thermostat opening. It will obviously happen after it reaches operating temperature, so watch after gauge gets close to there. Wait until you see that flow 2 or 3 times or fan comes on and off before you put cap on, and fill return bottle to proper level as well. That should cure it, by getting air out of system, and coolant flowing through heater core.

Did you re-fill coolant with heater turned on ?(not defrost) Leave rad or coolant return bottle cap off when engine cold, and turn heater on and add coolant as needed to keep level up. Let engine get to normal operating temperature, and wait for rad fan to kick in and out, indicating thermostat has opened, and coolant is circulating. Let that fan kick in 2 or 3 times and keep adding coolant as needed, and check heat periodically to see if starting to throw heat. When your getting good heat, put cap back on, top up return bottle, and you should be good. I suspect an airlock in heater core. I don't see the year anywhere so I'm guessing you have a rad cap, and if that is the case, leave it off as described, and watch for increased flow in rad when it gets up to normal operating temperature, which tells you thermostat is opening. Watch for that flow, 2 or 3 times, and you should be getting heat by then. If that isn't cure, get back to me with more info on year, engine etc. Keep me posted on your progress.

could be waterpump?
i was going to say rad fan,but if so heater would be hot.
lack of coolant will make heater core to blow cold,if engine heats up with full coolant,usually means poor or no circulation.
water pump?
run engine with full coolant,at operating temp.with rad cap off and look in rad cap hole and see if there is movement of water inside rad.
[rad fan will not come on if water is not circulating through rad water pump?]

Remove and raise upper hose at thermostat end and remove lower rad hose.
Fill rad with a hose and watch for flow from bottom rad hose and/ or bottom rad hose connecton.......water should fall though rad easily.
Honda rads are cheap.....any restriction....replace rad.

Remove thermostat....fill thermostat housing with hose and watch for water flow at bottom rad hose.
Flush good.

Remove heater hoses.......flush back and forth until a good flow is present "With heater control set to hot" if no or poor flow....replace heater core.

Stop leak can plug everything.

Also.......not likely causing over heating....but ....at your mileage,if you do not know if the timing belt has been changed.....CHANGE IT NOW!
Water pump is optional at this mileage.

you may have a couple different problems. the thermostat may be stuck open hterefore not allowing your engine to heat up properly. the coolant will just circulate through the engine and rad without heating up to proper temp. the other problem you may have is that you might have a plugged heater core thus not allowing the coolant to circulate through the core and give you heat.
I would recomend checking the thermostat and see if it is operating properly. an easy way to check it is by opening your rad when the engine is cold. start your truck and watch the coolant in the rad. If the thermostat is stuck open you should see the coolant circulating through the rad. This is not always the best way to check but it is an easy way to see. the other way which involves a little more work is to take the thermostat housing off and physically inspecting the thermostat.
hope this helps you out

Pretty common on those. I used CLR and disconnected my heater hoses & with a small pump, I ran CLR only, through the heater core, and let it sit in there overnight, flushed it through again next day, back flush as well. re-connect hoses, run engine with heater on, and rad cap off until the rad fan comes on 2 or 3 times, then put cap back on, to bleed air out of system. Cleaned it out enough to get the heat flowing again. If you changed thermostat and didn't let it run with heat on, and rad cap off for a while as described above, then do that first, just to make sure you haven't just got an air lock in the system.