Where is a heater core located on a mazda b4000 4x4 truck

After you remove the hoses from the core, remove the nuts and bolts that secure the heater case to the firewall in the engine bay. Inside the cab you will have to remove the glove box assembly for clearance. then disconnect the blower fan wiring. there may be another bolt securing the heater case to the firewall on the inside of the cab. Then you should be able to remove the heater case. You'll have to split the heater case to get to the core.

This is a re-badged Ford ranger so watdh the video of rthe ranger heater core change out. How To Replace Heater Core On Ford Ranger

Heater theromstat is faulty, it is located near the heater core in most vehicles, It monitors the temperature of the core or in some vehicles the inside cabin temperature and open or closes allowing heated water to flow through your heater core. Look on your heater hoses and you will find it. Most of the time its a DIY job and not that expensive but don't bet on it being cheap, they are proud of some of those things. Just have to check with your local parts house and find out. Used to be a common problem but I guess technology has caught up with them. Hope this helps.
Gillight

First check your fluid in your radiator if its low your heater will not work. Check all your heater hoses and make sure they are not kinked.
Your heater core may be plugged That will stop the heat flowing as well. If it's the heater core it will have to come out and replaced most likely. Not sure if there is a heater valve on that car.

OK if heat no blowing out just cool air #1 check your engine coolant level add if needed to res bottle and radiator, (wait until engine is cool to the touch before opening the radiator cap under pressure when hot!)#2 if good on coolant and your engine is getting to normal opperating temp as always you may have a clogged heater core, if so you can test the heater core flow by removing the to heater hoses mounted at fire wall in your engine compartment and with a garden hose at low volume push water through one of the two copper hoses coming out of your fire wall if the entering amount of water is coming out the other copper pipe then your heater core is good.#3 then if all the above is good and working your dealing with a blend door not operating properly inside your heater box located under your dash (not for the non experience to repair)

Inspect/Replace If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core.
When a heater core leaks, a new heater core is installed or the old one repaired.
Heater Housing

• The heater housing is usually under the dash and must be removed to gain access to the heater core.
• Procedures for replacing the heater core vary with the year, make, and model of car. It threfore necessary to consult the manufacturer's repair manuals for the proper procedure for replacement.

The heater housing is disassembled to get to the heater core. Heater Core

• Remove the access panels(s) or the split heater/air conditioning case to gain acess to the heater core.
• Remove the heater coolant hoses.
• Remove the cable and/or vacuum control lines (if equipped).
• Remove the heater core securing brackets and/or clamps.
• Lift the core from the case. Do not use force. Take care not to damage the fins of the heater core when removing.
• To reinstall the heater core, reverse the removal steps.

When the heater core leaks and must be repaired or replaced, it is a very difficult and time-consuming job primarily because of the core's location deep within the firewall of the car. For this reason always leak test a replacement heater core before installation.

if the operating temperature for the engine is normal, i would check to see if the valve that directs hot coolant to the heater core is moving. good luck.

The only thing to do is get a diagram from the MAZDA dealer parts dept. "A few parts fell out" is way to vague to help you.

do you have a air controlled heat valve switch located on firewall at heater core hose by chance on this vehicle?