Thanks for the reply FLEETSIDE but it does not have a green or an inductive pickup. All it has is a volt meter on one side and an amp meter on the other. hookups are a pair of RED and BLACK under each gauge,one pair labeld AMPS., OTHER VOLTS.The clips on the AMPS side have screw down clamps to hold a good connection. In the center is a large red knob LABELD in clock wise rotation, DIRECT, FIXED LOAD, VARIABLE. Above that is the fixed load switch,3 position 3/4,1 1/2,7, OHMS. Below the volt meter is a VOLT METER CHECK push button, And to the right of that is a VOLTS SELECTOR SWITCH, 4,8,16 VOLTS. Ive looked in some older high school auto books and they show similar types [MAYBE SAME BRAND] But are not same mod. [ more options ??] Is seems that i was right in that it is used for ckecking ALT/ GEN / BAT. Charge rate , cut in /out. but to the correct hookup im lost, i hope someone can help and give me some clues :confused: