help diagnose my weird electrical noise [video]

[tewhalen]

My 1987 cabrio has been resting quietly all winter in my garage, with the battery unhooked. Upon re-connecting it, it started making this weird clicking/ticking/pinging noise in the driver-side footwell. Here's the video:

https://www.youtube.com/watch?v=djdvSdLKJPQ

Obviously, this is very disturbing. I pulled fuses until it stopped: something connected with fuse 21 is the culprit. It's a ratsnest back there, so I can't quite tell where it's coming from or what exactly the noise is. Can anyone with better ears than me recognize this sound?

(The car started fine on the first try, everything else seems fine. It certainly wasn't doing this when we put it away in October, so maybe something got cold/cracked/corroded over the winter? Just guessing.)

[dlmrun2002]

Sounds like a relay trying to do it's thing but going gonzo on you.

dlm ny country

[Jaxx_]

Chime relay? Close the door and see if it stops. Do these cars check for seatbelts too? I haven't had my chime in years

[AndrewBird]

Definitely a relay going crazy. The ABS relay is right around there.

[tewhalen]

UPDATE: This spring, I'm doing some work on the front speakers and had the kick panel open and the speaker out. Decided to investigate this a little further since it's all open, and what do you know - the sound is actually coming from below and behind the speaker – it's the "interior timer light control" relay.

"Aha!" says I, "it's probably the switch that detects whether the door is open/closed that's failing, and it's causing the circuit to bounce and triggering that relay!" Put my finger on the switch and wiggled it a little, and sure enough, the relay starts going crazy. So it's the switch. Part # 61311370805.

Now, am I going to spend $27 to buy a new one, or am I just going to disconnect it...

UPDATE 2: Pulled it out and gave it a closer look. "That's barely a switch at all! It's just a spring and some metal contacts, and those contacts look crusty!" So, I cleaned it off with a tiny little wire brush and some brake cleaner. Plugged it back in and it seems to be working fine now. Will keep an eye (ear) on it.