Help! I've got this device that I feel responsible for getting working and I want to test its circuits. It is currently dead. It's this seat cushion heater. The attached pic is the handheld controller. Power comes in from an AC adapter or a 12V cigarette lighter adapter. The other wires go back to the device and control various heaters, fans and vibrators. One set of wires goes to a dead-man switch that deactivates all electronics if there's no one in the seat. First step: using a multimeter, I've verified that the power supply is indeed reaching the board. Second step: check the fuse. Um... could someone verify how I test a fuse with the multimeter? I set the dial to Ohms and, if it's blown, I should read infinite resistance across it, right? i.e. the needle should not move. But it does give me a reading. It gives me the same reading as when I short the leads together. So that means fuse is OK, right? Now I'd like to verify that this dead-man switch is working. I cannot find the switch itself (I've looked extensively). But it seems to me that I should find some combination of two of those off-board wires that read an infinite resistance when I'm off the seat and less-than-infinite resistance when I sit down. So far, all pairs read less than infinite resistance, but I'll have to do an exhaustive check. While I do that, anyone have any suggestions (I mean other than 'take it back to the store' and ' don't buy that junk') as to how to proceed?