The mystery be solved

It's hard to see amidst the spaghetti jumble of wiring but the mystery is solved. I'd made a small error in my interpretation of the wiring diagram. Now, when the correct code is entered, the buzzer sounds for 5 or 6 seconds. My next task will be to time my door unlocker. I believe it takes about 5 seconds to open. If not then I might just have to enter the code twice to open the door. Not a major problem!

It turned out that I had to connect the purple wire to the negative, the blue wire to the black wire of my buzzer and the red wire to the positive. Now that's all sorted out, I can get the rest of my door lock working. There is an alarm setting whereby an alarm can be set to sound if the wrong code is entered. I have no specific use for that piezo buzzer so I might assign that as my alarm. It's certainly loud enough!

Why I'd made the elementary mistake before was simply from tiredness. I get so many interesting issues on the special needs schoolbus I drive for work that no day is standard and no journey is routine. I get exhausted by the end of the day. Today, for example, I'm home and so tired I'm literally walking into things. But at least my door unlocker keypad is closer to being installed.

Siting the keypad is an interesting issue. If I put a keypad hatch then somebody nefarious might open it to see what's under the hatch. I could mount it inside the fuel hatch but as I'm going to put a lock on that, it wouldn't be smart. I thought of mounting it underneath but I might be parked on soft mud and might need access when I'm in my Sunday best. I'll find somewhere.