We need a heater hose assembley for the rear unit.

have you checked the coolant level? also the hoses after the engine has been running for a while should be more than warm, they should be hot. the in hose should be so hot you can not hold on to it for long.

you may have a plugged heater core, try removing hoses to front and rear units and use a water hose to flush, do this good, start withfront one stick hose on one hose and see what comes out the other end of the core, then which to other end of the core, you may need a small hose about 3ft to slide onto heater core end to then put hose nozzle on the other end of small hose then hit handle to force water through. do this to both cores.

at first i just bypass the heater core assem. go from the thermm. housing to the head nipple. if you put your heat setting to hi setting all your coolant will pour out that nipple with no hose. if you drive like that BOOM! engene blows the heater hose assembly replacement for that is $90+tax and thats bs. ireplaced mine with 2 tees it works great! it runs cooler than it ever has and the heater works when you need it. that assembley has a thermal crossover valve in it and i find no reason for it other than the heater may work a couple min. sooner.And or the coolant that ain't worth $90bucks+tax to me.i can wait a couple min, longer for the heater to work i used the tees to maintain water flow through the head nipple back to the rad,when heater is not in use. incase that was the purpous of the thermal valve crossover. i could find no one who could tell me its intened purpous at any parts store or even the GM dealership.

Heater Core REMOVAL & INSTALLATION

1. Disconnect the negative battery cable. Pinch off the hoses to the rear heater core.
2. Raise the vehicle and support safely. Disconnect the underbody heater hoses from the rear heater core tubes.
3. Remove the middle bench, if equipped. Remove the interior left lower quarter trim panel.
4. Remove the 7 screws that attach the air distribution duct to the floor and unit. Pull the distribution duct straight up to remove.
5. Remove the 6 screws from the top surface of the unit and remove the unit cover.
6. Pull the heater core straight up and out of the unit.
7. The installation is the reverse of the removal procedure.
8. Connect the negative battery cable and check for leaks.

Here's an excerpt from the 2002 Acura MDX 4WD 6cyl Repair guide for replacing what the reference manual calls the "control assembly" - its located under the console rear trim and may (or may not)
contain the blower resistor - my manual doesn't say - but this is the closest thing I could find for you. Every other blower resistor I've had to find was located close to the heater controls - and this
car seems to be no exception -- its heater controls are located in the console between the seats, rather than in the dash (as in Acura 2003-06 MDX models).

You may want to call your friendly Acura dealership ad speak to the parts department, to make sure where the blower resistor is located - or a visit to a dealership parts counter often (or
Advance Auto Parts is helpful too) ofen clarifies questions I have from Haynes manuals (the cheapest car repair guides).

All this assumes that you've correctly diagnosed your blower control problem -- as in "replace the blower resistor when the blower works only on the MAX/Highest setting."

-- begin excerpt from 2001-2 Acura 4wd 6cyl MDX Repair manual --
Control Assembly Removal & Installation

2001-02 Models

1. Remove the console rear trim. Refer to the accompanying illustration.
   
   

   Fig. Exploded view of the console rear trim
   

2. Remove the self-tapping screws and the rear heater-A/C control unit (A) from the console rear trim (B).

To install:

1. Install the control unit in the reverse order of removal. After installation, operate the control unit controls to see whether it works properly.
2. Run the self-diagnosis function to confirm that there are no problems in the system.
   
   

   Fig. Remove the self-tapping screws and the rear heater-A/C control unit (A) from the console rear trim (B)
   



--- end excerpt from 2001-2 Acura 4WD MDX 6cyl Repair Manual ---

Simple check is to determine if the engine coolant is getting to the rear unit. Two heater hoses run from the firewall, passenger side, under the car to the rear. At the firewall there is a 4 hose connector, heater control valve, that controls the amount of coolant to the rear unit. Sometimes it will plug up, some times the heater hoses will plug up, some times the control valve will not get the command to open with a vacuum hose.

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.

Any competent repair shop with a scanner should be able to pull codes from the ABS computer. It is likely a speed sensor or wire.

passengers side carpet sounds like a broken {{ heater-core }} although im not actually there to see oit best way to determine this is to first 2 people one inside the vehicle the other with a garden hose and look for the leak 2nd alternative open your radiator cap and see how much fluid is lost run the heater full there can be also seen running down from inside the passengers side where the heater core is located it will most definitively be 1 of them .

open the trunk remove the scuff plate that is located on the back part of the trunk closest to you. then pull the carpet back on the side that you are trying to get to and remove the three or four nuts holding the light assembley in. pull the assembley away from the body then disconnect the bulbs from the assembley. thay should just turn and come out socket and all.

many vans have rear heater cores for added passenger comfort, so this is not unusual, it is very possiable either the hoses or there connections to the rear eater core are leaking or the heater core itself is leaking.