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Electrical shock by alarm remote lock button when alarm sounding?

I have a headlight problem, so I was checking most of my fuses, since some aren’t marked. When I replaced one of the fuses I had pulled, the alarm began going off. After I replaced the fuse, while the alarm was sounding, I hit the Lock button of the remote. My thumb was zapped! It felt like I’d put it into a light socket, but probably not as strong. The zap was steady until I removed my thumb. That didn’t turn off the alarm, so I then hit the unlock button. I wasn’t zapped that time. I was under the dash and my keys may have been touching the carpeted floor. I might have been touching a metal surface with my other hand, but I don’t know.

Did the zap originate from the remote or if not, where?

(I know, I should repeat the experiment, but would rather not set off the alarm for now.)

The remote can’t generate enough voltage for you to feel, and certainly not through the rubber key. An ESD discharge is possible (the voltage build up would come from you), but it would be a single quick pop not the continuous experience you are describing (It’s unlikely in the position you were in any way.)
I’m going to guess that it’s some sort of nerve issue in you thumb and you were holding it just right to trigger it [the nerve].

Maybe I should add that I was kneeling on the ground and lying over (in contact with) the metal edge along the doorway.

I find the nerve issue hard to believe, as I have experienced nerve issues (not in my hands & not motion related), but this was a different experience. I once stuck my finger in a live bulb socket as a kid… that is what this felt like. (And I might add, I didn’t experience anything in my thumb when I pressed in all those fuses!) The keys weren’t in the ignition, but the alarm was going off. I had contact with metal keys, but the tip of my thumb was touching plastic.

Was that an after market alarm or OEM. Both seem to have more than their share of problems, but OEM seems better.

It’s apparently an OEM alarm… I found the Subaru Alarm/Protection System instruction sheet in the car after I bought it.

Neither the voltages used in the remote or in the car itself are high enough for you to feel a shock on undamaged skin. (with the exception of the car’s ignition system, which is a different story) I think it takes around 45 volts to overcome the resistance of your skin. Plus the plastic of the remote is a good enough insulator that you could have hundreds of volts under it and not feel it. It’s possible you were pressing on a nerve or something.

That said, I remember working on an old TV remote control (one of the pre-IR ultrasonic ones, and getting my finger on the board while a button was being pressed. I was amazed that it gave me a shock and a little burn. So it is possible if a circuit in the remote is generating a higher voltage than the battery, but I find this extremely unlikely in the case of the transmitter in a feeble car remote, which puts out a fraction of even what a cell phone does, which itself only puts out less than a toy walkie-talkie. Plus the plastic insulator. Neither the battery or RF energy is enough to feel.