Replace rear heater core - 2003 Chevrolet TrailBlazer

I couldn't find a heater hose diagram specific to the 1999 Chevrolet Venture with rear heat and air, but I can give you the general location of the heater hoses and how to identify which ones go to the rear heat. The heater hoses on a 1999 Chevy Venture are located on the passenger side of the engine compartment. There are two heater hoses, one that is hot and one that is cold. The hot heater hose will be connected to the heater core, which is located under the dashboard. The cold heater hose will be connected to the engine. To identify which heater hose goes to the rear heat, you can look for the hose that is connected to the heater core outlet that is labeled "Rear Heat." The other heater hose will be connected to the heater core outlet that is labeled "Heating Core Inlet." Once you have identified the heater hoses that go to the rear heat, you can reconnect them to the heater core. Be sure to use new clamps when you reconnect the hoses. Here are the steps on how to replace the heater hoses on a 1999 Chevy Venture with rear heat and air: Disconnect the negative battery cable. Drain the coolant from the radiator. Remove the heater hoses from the engine and heater core. Install the new heater hoses. Fill the cooling system with coolant. Reconnect the battery cable. Start the engine and check for leaks.

Hi Lerverne,here' a link on your rear heater core. Repair Guides Auxiliary Heating Air Conditioning Heater Core AutoZone com Here's a link to a new rear heater core. Spectra Premium Heater Core

For heater core replacing procedure. I suggest you to go through this related help links.Its all complete step by step procedure: ----How to replace heater core for All car models?

Click the link below: ---

http://technoanswers.blogspot.com/2011/11/how-to-replace-heater-core-for-all-car.html

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How to Flush Heater Core?

http://schematicsdiagram.blogspot.com/2011/12/how-to-flush-heater-core.html

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How to Remove Heater Core ?

http://howtobyme.blogspot.com/2011/12/how-to-remove-heater-core-on-2008-honda.html
Heater Core Replacement?

http://howtobyme.blogspot.com/2011/12/honda-heater-core-replacement.html

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To replace heater core?http://technoanswers.blogspot.in/2012/02/how-to-replace-heater-core-on.html------

How to replace heater core?http://technoanswers.blogspot.in/2012/02/how-to-replace-heater-core-on_10.html
How to replace heater core on Buick Regal?

http://howtobyme.blogspot.in/2012/02/how-to-replace-heater-core-on-buick.html
----------This will help.Thanks.

Hi, this is the heater core for your rear heater. If it's leaking from inside the box, it's likely the core is bad. Please let me know if you would like instructions for replacing the rear heater core. A new core is $92 at autozone, but I would shop around. Make sure you specify the rear or auxiliary when ordering a new new core, as the front core is different.

Is the correct type of heater core that use for rear heater?Check fan fix its correct side,or wiring change or return water line is blocked.

If the tubes going to the rear heater core are the problem , drain the system and replace the bad tube/tubes. If the actual heater core is leaking and you do not want to go to the expense of replacing it, unhook both tubes at the back of the motor , cut out a good section of hose and use it to loop/connect the outlet line and inlet line on the motor side (not the rear heater core side). This will bypass the rear heater core , the front heater core should be adequate to heat the whole car. If you have a pin hole in a section of solid (copper) tubing, you can cut out the bad section and reconnect it with some heater tube and two hose clamps.

REMOVE OR DISCONNECT

1. Negative battery cable.
2. Drain cooling system.
3. Upper firewall weatherstrip.
4. Upper secondary cowl.
5. Heater hoses from core.

NOTE Blowing out residual coolant from inside the heater core will prevent coolant leakage into the passenger compartment when the heater core is removed.

1. Sound insulator.
2. Rear seat duct adapter.
3. Heater duct.
4. Heater core cover.
5. Heater core.

INSTALL OR CONNECT

1. Heater core.
2. Heater core cover.
3. Heater duct.
4. Rear seat duct adapter.
5. Sound Insulator.
6. Heater hoses to core.
7. Upper secondary cowl.
8. Upper firewall weatherstrip.
9. Fill cooling system and check for leaks.
10. Negative battery cable.

Heater Core Removal & Installation Front To Remove:

1. Make sure you have the anti-theft codes for the audio and the navigation system, and then write down the audio presets.
2. Disconnect the negative cable from the battery.
3. From under the hood, disconnect the heater valve cable from the heater valve. Turn the heater valve arm to the fully opened position.
4. When the engine is cool, drain the engine coolant from the radiator.
5. Disconnect the inlet heater hose and the outlet heater hose from the heater core.
6. Remove the mounting nut from the heater unit. Take care not to damage or bend the fuel lines, the brake lines, and related parts.
7. Remove the dashboard.
8. Remove the evaporator.
9. Remove the mounting bolts and remove the heater unit. Front heater unit
   
   
10. Remove the self-tapping screws and the clamp.
11. Carefully pull out the heater core so you don't bend the inlet and outlet pipes.

Front heater core

To Install:

1. Using care, install the heater core to the heater unit and secure.
2. Using care, install the heater unit and tighten mounting nuts and bolts to 7 ft-lb (10 Nm).
3. Install the evaporator.
4. Install the dashboard.
5. Connect the inlet heater hose and the outlet heater hose to the heater core.
6. Connect the heater valve cable to the heater valve.
7. Refill the cooling system with engine coolant.
8. Adjust the heater valve cable.
9. Make sure that there is no coolant leakage.
10. Make sure that there is no air leakage.
11. Connect the negative battery cable.
12. Perform the power window control unit resetting procedure.
13. Enter the anti-theft codes for the audio and the navigation system, and then enter the audio presets.

Rear To Remove:
NOTE: The rear blower motor, the rear heater core, the blower screen, the rear blower resistor (heating/air conditioning system) and the rear power transistor (climate control system), the rear air mix control motor (climate control system) , the rear mode control motor and the rear expansion valve can be replaced without removing the rear heater-A/C unit.

1. Remove the self-tapping screws and the clamp, and then remove the bolts and the rear evaporator lines with the rear expansion valve. If necessary, remove the rear expansion valve. Use a second wrench to hold the other fitting on the valve so the rear evaporator lines won't twist. Leave the first fitting loosely connected so you can use it to hold the valve while you loosen the second fitting.
2. Remove the rear heater hoses.
3. If necessary, remove the rear blower motor, the rear heater core, the blower screen, the rear blower resistor (heating/air conditioning system), the rear power transistor (climate control system), the rear air mix control motor and the rear mode control motor.
4. Remove the self-tapping screws and the lower housing.
5. Remove the self-tapping screws, and carefully separate the left upper housing from the right upper housing. Remove the rear heater core.

Rear evaporator assembly

To Install:

1. Replace the rear heater core.
2. Attach the heater hoses.
3. Make sure no air is leaking from the left upper housing and the right upper housing fitting and from the upper housings and the lower housing fitting.
4. Before reassembly, make sure that the rear air mix control linkage and door move smoothly without binding.
5. Before reassembly, make sure that the rear mode control linkage and door move smoothly without binding.
6. Reassemble the housing.
7. After reassembly, make sure the rear air mix control motor runs smoothly.
8. After reassembly, make sure the rear mode control motor runs smoothly.
9. Refill the cooling system and make sure that there is no coolant leakage.

You need to replace the front one, that one sit under the dash, your truck has front and rear a/c and heater, the rear heater core is for the rear unit, that heater core is to give you heat for the rear unit, that heater core sit in the rear of your truck inside on the side, that one don't have anything to do with the front one leaking, order the one for the front unit. hope this was very helpful.

Drain the engine coolant. Refer to Draining and Filling Cooling System in Engine Cooling.
Remove the heater hoses..
Remove the heater core tube clamp bolt.
Remove the heater core tube clamp.
Remove the heater core shroud seal.
Remove the heater rear case bolts (Remove the heater rear case.
Slide the heater rear case downward in order to disengage the upper case clip.
Remove the heater rear case.
Remove the instrument panel (IP) compartment door. Refer to Door Replacement - Instrument Panel (I/P) Compartment .
Remove the heater core clamp bolt
Remove the heater core clamp.
Remove the heater core