Two things I'll throw out.

1. Until resolved, under the hood remove the cable from the heater control valve and manually close it.

2. Run a new wire from G401 to Pin #9 and see what you have then? If that "temp" ground brings everything "back to life"...the decision tree goes from there. If that "temp" ground does not bring things back to life there is more testing to be done.

I jerry-rigged a temporary ground wire from the pin in the connector to the G401 and still no continuity. Could the connector be bad? Or does the unit have to be plugged in to check for continuity?

PLEASE don't take this wrong but something just isn't adding up here.

You run a wire from G401 to Pin 9 and still do not have continuity through the wire?

When your meter is set to test for continuity, touch the two leads together....what does the meter display?

No, you're fine. I agree that something's not adding up and I'm rather confused. When I touch the multimeter probes together it registers 0v. The continuity symbol is the one that looks like an arrow and a positive sign put together, right?

EDIT: I just did some research and found out that the symbol I referred to above is the diode check symbol. I discovered that the continuity check symbol is the one that looks like a Wi-Fi symbol. Went and tested the wire again and found that there is continuity in the ground circuit. I felt like such a dingbat. Lol Unit shot?

Just to double-check it is not a power or ground issue:

1. At the rear of the heater control panel is a 22P green harness connector. Unplugged that.

2. With a voltmeter's red lead touching the Wht/Yel wire terminal (terminal no. 3), touch the voltmeter's black lead to body ground (for example, metal bracket or unpainted bolt on car's body). Is there voltage and what is the voltage measurement?

3. If there is voltage in step #2, then with voltmeter's red lead still touching the Wht/Yel wire terminal, touch the voltmeter's black lead to the Blk wire terminal (terminal no. 9). Is there still voltage and is it about the same measurement as in step #2?

4. Next test for voltage at the Blk/Yel wire terminal (terminal no. 2) with the ignition switch in position II (ON). Voltmeter's red lead to Blk/Yel wire terminal and voltmeter's black lead to body ground. Is there voltage and what is the voltage measurement?

Test 1: 12.48V. Test 2: 12.54V. Test 3: 12.20-12.25V.

I went and found this thread (https://www.hondaaccordforum.com/foru...s-49643/page2/) and soldered the wire between the two points shown in the picture, and it works again! The only issue left with it is that three of the lights don't work. One of them flickers when selected, and two of them don't work at all.

The lights not working may be due to bad through board vias. See post #5 in this thread:

Heat/AC Control indicator light - Honda-Tech

Checked out the link and made the repairs outlined in post #5. The light that flickered is now working properly, but one light is still out and the other that was out flickers. It even stays on and flickers when the car is shut off.

Okay, so I resoldered the jumper wires and now all of the upper lights work as well as the A/C and rear defroster indicators. But now the recirc indicator does not light at all. Tried resoldering that wire a couple of times and it still won't work. Could the bulb be shot, or am I just going to have to replace the whole circuit board?

Bump. Anyone? I don't mean to seem impatient, but I'd like to try and fix this without having to get a replacement board, if at all possible.