I’m going to hook up a voltage gauge in my car tomorrow if the weather doesn’t suck. Negative wire needs to be grounded, and positive wire... Spliced into a constant 12v source? That sound right?

The internets told me to avoid an ignition wire because that would lead to a bad reading, and the internets also told me to pick a wire that will allow me to get a read while I’m turning the key to see the battery/alternator/fairy-prison health while cranking.


That’s all well and good... But uh. I don’t know how to do that. Just find any 12v constant and I’m good..? I have wire taps and I imagine they’re easy enough to use.

The internets also mentioned using this handy dandy tool below to check which wires have power when the engine is off (and when the key is turned to accessories, I imagine..?). But uh... Despite keeping it in my tool box I don’t have the slightest clue how to use this. Anyone want to give a quick “digital multimeter for dummies” lesson?

Tl:Dr - how da fuq do I wire a voltage gauge.

Bonus round! My belt squeel is getting rediculous. It’s only on startup, for anywhere from 20 seconds to two minutes. If I go for a drive, shut my car off and turn it on again within like five minutes there’s no startup squeel. Cold seems to make it a bit worse, maybe. The number of accessories running definitely seems to make it worse. Throttle position and/or rpm greatly increase the sound. Whether or not the clutch is in seems to effect things as well.


What’s your diagnose? I’m thinking alternator, timing belt or accessory belt pulley...