I was able to reach pin 9 with the voltmeter probe with the PCB installed in the car, so I know it's not inadvertently in "dot mode." Hopefully I'll find time later today to take the board out of the car and check the continuity of all the solder joints that could affect the first IC. In the meantime, here are two photos I took of the PCB before I installed it in the car; maybe there's some error that will be immediately apparent to you that I haven't noticed in the course of checking, double-checking, and triple-checking my layout vs. your schematic. If it looks like the second IC is missing its +12 V power source, that's because I ran out of room on the 2" x 3" board, so power for the second chip is provided by a copper bus bar that runs across the two mounting standoffs upon installation. Also note that external connections #2, 3, and 8 (counting from the top) and associated components (2 resistors, 1 diode, 1 transistor) are not part of this circuit (they're for a battery-related warning light on the instrument panel) and that ground/earth is provided on both external connections #1 and 5.