Hey Derp (Derp=newbie in this case) 1st; I'm just warning you in a way that will get your attention, so I'm not going to sugar coat it...
two more pennies in the fuse box wont solve anything...so on we go.
2nd; you're not stupid at all, just not fully informed & looking for answers. PS I'm a Journeyman electrician, I work with 480/3 phase all day, so I don't F_around at all when it comes to electricity. I want you to be safe. You work with automotive systems, so you know most of the basics, this is good.
you need to know your machines amp draw. if you ID plate is missing, there is usually another plate on the Compressor deck itself, if that's gone or unreadable, then we're on our own.
So, anyway, if you have the machine on a 20 amp breaker & it's tripping, ( assuming it's not a GFI-breaker) then you will see a momentary surge of current upon startup maybe as much as 20+ amps & it should then drop down to about 4-8 amps typically within about 1-2 seconds MAX, depending on what size your compressor is.
If it starts with a high Amp draw & stays there, then either it's mechanically seized up, ( called a locked rotor) the start/run relay is stuck/bad, or your run winding is open. But, if the breakers tripping before the compressors over current "clicks" off, then you have a hard short somewhere. unplug the machine.
I'd take the terminals off of the compressor & OHM check between each & the metal of the compressor housing to check for shorted windings, ( scratch through the paint to bare metal) anything other than infinity ( an open circuit, you know the drill) it's a trashed compressor,
next measure between each of the terminals , you should be able to see both the start winding, run winding & common terminal respectively, you can see the pinout ID on the "pinned" topic at the top of the "refrigeration" discussion area. if it checks out OK, proceed....
Go to home depot, go down the electrical aisle & get a handy dandy appliance "plug in line load" tester, it costs about $25.00 You plug it into the wall outlet & plug your machine into it with the thermostat in the off position, the display can be set for Amps or Watts, (you of course will be looking at the Amps draw) you should make sure the machine is about the only big appliance on that breakers line.
With the machine now plugged into the Load tester & the compressor OFF (via the thermostat) you will see the machines load on the line ( the evaporator fan, coinmech load, the lightup sign, etc.) make a note of it, It should read about maybe 2-amps....Now turn the thermostat ON & note the Amp draw, (hopefully before the breaker pops) a locked compressor will read high & stay there until the overload trips out ( sometimes it's also called the Clik-ette) or the houses circuit breaker trips. if so, it's going to have to be determined if the compressors really locked, of you have a bad start/run relay, an overcharged system. etc. See what you get & proceed from here.
