You have purchased a ' Carbon Pile ' VAT or Voltage Amperage Tester and it's quite a good machine there regardless of who made it - you'll need a shunt or some other kind of switch to cut the battery circut after you've started the engine for most charging system tests ~ Sun used to seel a nifty knife switch that had a female battery clamp on one end and a male battery post on t'other for just this purpose .
When load testing a generator or alternator remember : _NEVER_ load the divice below it's rated voltage ! Ex : 12 volt 35 amp. alternaotr will charge 40 + amps if you load it down to 10 voltsa but you'll prolly kill it doing so .
This device can also test starters on the truck , look for under 150 amps draw .
My guess , if you take it to the local high school auto shop or college evening adult school auto shop the teacher will be able to show you how to use it , make up a crib sheet and laminate it @ Kinko's & keep with it for future reference .
I have been hunting for a SUN VAT40 for some time now , need not be pretty but it's gotta work .
