Heater Control Unit (A/C) help

datechboss101 · Oct 29, 2017

Basically, over the past year or so the OE HCU is intermittently working, and the recirculation mode doesn't work. I would like to DIY fix this, as I may end up driving Lucky to Miami and back every week or so from June due to University. What is the best fix for this, as Honda decides to discontinue parts for the CG Accord? Also, I went to the junkyard and grabbed a few HCUs and those weren't working at all.

SupraGuy · Nov 3, 2017

From the repair manual, Section 21, page 22: Recirculation control Motor Test

1. Disconnect the 7P connector from the recirculation control motor.
[NOTICE]
Incorrectly applying power and ground to the recirculation control motor will damage it. Follow the instructions carefully.

2. Connect battery power to the No.1 terminal, and ground the No.5 and No.7 terminals; the recirculation control motor should run smoothly. To avoid damaging the recirculation control motor, do not reverse power and ground. Disconnect the No.5 or No.7 terminals from ground; the recirculation control motor should stop at Fresh or Recirculate. Don't cycle the recirculation control motor for a long time.

[there is a diagram of the 7 pin connector at this point. It is flat on the bottom, and is raised at the odd numbers, with 3 and 5 slightly higher than 1 and 7.]

3. If the recirculation control motor does not run in step 2, remove it then check the recirculation control linkage and doors for smooth movement.
* If the linkage and doors more smoothly, replace the recirculation control motor.
* If the linkage or doors sticks or binds, repair them as needed.

Recirculation Control Motor Replacement

1. Remove the glove box (see page 20-87).

2. disconnect the 7P connector (A) from the recirculation control motor (B). Remove the self-tapping screws and the recirculation control motor from the blower unit.

[ diagram of the motor and wiring harness with reference to the glove box follows, wires labelled as (A) and motor as (B) The screws referred to are two which go from the right hand side through brackets on the motor. ]

3. Install the motor in the reverse order of removal. After installation, make sure the morot runs smoothly.

Edit: My HCU is acting quite badly as well, the controls will sometimes not light up while the car is running. I can still control fan speed, but I cannot select different vents, turn on A/C, rear window defrost, or change the temperature mix (I can turn the dial, but it does nothing) while it is in this state. A little pressure on the back of the module (Pulling out the clock, and reaching in back there) will usually get it working. A bit of percussive maintenance did the trick for a while, but it takes a bit more finesse to do it now. This was it's intermittant issue before, but yours sounds different.

datechboss101 · Nov 4, 2017

SupraGuy said:
From the repair manual, Section 21, page 22: Recirculation control Motor Test

1. Disconnect the 7P connector from the recirculation control motor.
[NOTICE]
Incorrectly applying power and ground to the recirculation control motor will damage it. Follow the instructions carefully.

2. Connect battery power to the No.1 terminal, and ground the No.5 and No.7 terminals; the recirculation control motor should run smoothly. To avoid damaging the recirculation control motor, do not reverse power and ground. Disconnect the No.5 or No.7 terminals from ground; the recirculation control motor should stop at Fresh or Recirculate. Don't cycle the recirculation control motor for a long time.

[there is a diagram of the 7 pin connector at this point. It is flat on the bottom, and is raised at the odd numbers, with 3 and 5 slightly higher than 1 and 7.]

3. If the recirculation control motor does not run in step 2, remove it then check the recirculation control linkage and doors for smooth movement.
* If the linkage and doors more smoothly, replace the recirculation control motor.
* If the linkage or doors sticks or binds, repair them as needed.

Recirculation Control Motor Replacement

1. Remove the glove box (see page 20-87).

2. disconnect the 7P connector (A) from the recirculation control motor (B). Remove the self-tapping screws and the recirculation control motor from the blower unit.

[ diagram of the motor and wiring harness with reference to the glove box follows, wires labelled as (A) and motor as (B) The screws referred to are two which go from the right hand side through brackets on the motor. ]

3. Install the motor in the reverse order of removal. After installation, make sure the morot runs smoothly.

Edit: My HCU is acting quite badly as well, the controls will sometimes not light up while the car is running. I can still control fan speed, but I cannot select different vents, turn on A/C, rear window defrost, or change the temperature mix (I can turn the dial, but it does nothing) while it is in this state. A little pressure on the back of the module (Pulling out the clock, and reaching in back there) will usually get it working. A bit of percussive maintenance did the trick for a while, but it takes a bit more finesse to do it now. This was it's intermittant issue before, but yours sounds different.

Some pics would be helpful so I don't screw up anything! But, I will check it out.

Rusty Accord · Nov 5, 2017

You really need to download the FSM (Factory Service Manual) if you intend on working on your car. The link for it is in Accord Tech section, the 1st sticky. It's free. :computer:

datechboss101 · Nov 5, 2017

Rusty Accord said:
You really need to download the FSM (Factory Service Manual) if you intend on working on your car. The link for it is in Accord Tech section, the 1st sticky. It's free.

I did that, and I literally took ~15% of the car apart to find the motor (which resulting in me screwing up the battery connections few times), but couldn't locate it the motor, as the manual was very vague to where the motor was located and there was no youtube vids on it either for 6GA..

SupraGuy · Nov 8, 2017

I was taking my post from that FSM. There is a picture of the motor, it seemed clear enough to me, but it also appears that it may require the feed pipe to the fan to be pulled to see it.

kn0x47 · Nov 8, 2017

on page 1090 (21-3) of that FSM it shows where the recirculation motor is which is next to where your cabin air filter goes. buy a new recirculation motor and it'll be easy to see what you're looking for. it's a little hard to get to.

If your having intermediate issues with the climate control then that's a wiring issue. more than likely the wires going to the back of the climate control has been pulled on too hard when pulling the connects out so now one of them is loose. Push in each wire while the AC control is connected to make sure there's a good connection.

what parts have been discontinued??? just buy a new recirculation motor from rock auto

datechboss101 · Nov 10, 2017

kn0x47 said:
on page 1090 (21-3) of that FSM it shows where the recirculation motor is which is next to where your cabin air filter goes. buy a new recirculation motor and it'll be easy to see what you're looking for. it's a little hard to get to.

If your having intermediate issues with the climate control then that's a wiring issue. more than likely the wires going to the back of the climate control has been pulled on too hard when pulling the connects out so now one of them is loose. Push in each wire while the AC control is connected to make sure there's a good connection.

what parts have been discontinued??? just buy a new recirculation motor from rock auto

This is literally from Honda Corporate (Honda of North America): "Any car that is older than 15 years old is not supported (parts vise), so you must go aftermarket or junkyard."

I will check the area again... I was looking in that general area for the module. And I never pressed that hard on the connectors, but will check as it bothers my parents alot.

Going to see 21-3, as I skipped that page.