Spartan 12v solenoid terminal polarity

Four terminals or four positions?
There are control terminals and power terminals.
I guess in the relay are two solenoids, one for forward, the other for reverse.
A common terminal between the two solenoid and and two more terminals for forward solenoid and the other terminal for reverse solenoid, this is control circuit.
Four power terminals are open in normal position, normaly open contacts with solenoids not energized.
I'm guessing your question, if I'm guessing right and on the right track, reply to this answer so I continue explaining what happens with the four power terminals. It is basically a four way switch when solenoid is energized, reversing the polarity of the voltage to the load or motor.

that happens
what work has been done on the car recently

check battery cable to starter is sound
tight battery terminals
if starter motor clicks ..flat battery

if starter wont turn at all
possible faulty starter
or immobilizer is still activated

Hi Bob

Not much info to go on??

Usually don't need one
12v DC to posative (red)
12v Ground to Chassis or body of Amp
Possibly an Ignition Key 12v to hold memory settings
2 Speaker Unit will have 4 wires - 2 to each speaker
one wire of each pair will have a stripe (say negative)
keep striped wire to same speaker terminals to keep the speakers in phase with each other (speaker cones travel in same direction or you get distortion)
4 Speaker Unit - same as above but either Front Pair or Rear Pair.

Get the Amp on a bench & test the unit with a couple of cheap temporary speakers.

Good Luck
How to connect your car amplifier very simple explination and test

Part 1 How To Set Up PSU Car Amp Subwoofer In Home Re Do Video

Check battery and connection.

Here is the way to hook them up in series, or in parallel.
There are 3 batteries in top (series) pic, but a 4th would be added in same wiring manner. Disregard the letters "ve" in diagrams, but the +/- polarity is vitally important in hookup.
.
Note that four 12v batteries hooked up in series will be 48 volts at the end terminals. (If all four are hooked up in "parallel" then the total would still be 12 volts).

If you want to supply a 12v inverter, you need to hook 12v batteries in PARALLEL.

Which terminal? Large one? Small one? The large one should come from the battery, and always have +12V on it. ONE of the small wires should have +12V when someone has the key turned to the "Start" position - that wire goes to ONE of the small terminals (if the solenoid has two)... and if it does have two small terminals, then it COULD be either terminal - different manufacturers may not use the same terminals for the same purposes.

If the solenoid has two small terminals, then one terminal may be for "coil ballast bypass" or it might also be for "transmission interlock", depending upon which make & model vehicle we're talking about. If it's for ballast bypass, then when the solenoid is energized, that terminal will be internally energized so it can provide +12V to the coil (which normally gets only +6V in operation). If it's for transmission interlock, then that terminal will need to be grounded through a neutral safety switch to prevent the car from starting unless the transmission is shifted to Park (auto only) or Neutral (auto or manual), and/or the clutch pedal is depressed (manual only).

It'd probably help a LOT if we knew which make & model vehicle this is, and what type of transmission it has.

If the compressor has 3 air connections on top then the two lower terminals with nuts are the + and - supply inputs to the compressor motor. The two top spade terminals power a solenoid valve which changes a triple sequence (illegal?) to a combined blended triple tone. I don't think polarity is an issue but to check this connect a 12V battery -ve to the mounting bracket on the compressor. Attach 2 wires to a headlamp bulb and connect one to battery +ve. Then touch the spare wire to each of the 4 terminals in turn. If the bulb lights that terminal is at compressor ground. You can determine the operation of the relay in the same way. Between 2 terminals the relay will operate. Note those and then test each to the relay bracket to see if one side of the coil is grounded. By powering the relay directly from the battery you can then use the bulb to determine which contacts are 'made' when the relay operates. You will need a relay to control power to the motor. The solenoid valve probably only takes a couple of amps. You could run both the motor and the solenoid valve from the same relay if you just wanted a blended composite tone.

I presume the two leads you mention are:-
a) very heavy main +12V power lead from the battery terminal with approx 3/8" eyelug terminal,
b) less heavy wire that connects battery power to main vehicle fusebox for power distrubution- this cable may incorporate a fusible link.
The two leads (as above) connect onto the same heavy duty 3/8" terminal on the starter motor.
The lower 3/8" power post (closest to the motor housing) connects only to the starter motor and should not normally be tampered with.
There should be one more light duty wire that operates the starter motor engage solenoid .- This is connected back to the ignition switch 'Start' +12V control output.

You need a 12v lead to the ignition switch, a 12v lead from switch "run" terminal, to coil battery terminal. You also need a lead from the ign switch start terminal to the small post on the starter solenoid. Battery connects to engine block (-) and large terminal on starter.(+) This will give you start and run. Good luck...Hope this helps you!

Inspection: Connect the motor terminals directly to battery voltage (12V) and check that the motor operates smoothly. Next, reverse the polarity and check that the motor operates smoothly in the reverse direction. If the operation is abnormal, replace the motor.