I don't know specifically about your car, but I seem to remember that on some cars with remote battery there is a Red Positive (+) terminal under the hood that connected directly to the battery.

No Black Negative (-) terminal, they expect that you'll know that you can use the frame or other grounded metal for Negative...

Have another look for a Red plastic cap, pop it off and see if that's your Pos terminal.

Best Regards,
Jim