Ground it first with the negative.
the battery will have a - mark on it which means neg., and the cable that is bolted to the engine block is the neg. cable, the pos. cable will go to the starter.
Depends on the car. An E30 BMW neg battery cable is about 6 inches. The neg battery cable on a Chevy small block about 2 feet.
Electrical isn't your strong point, is it. If you take the neg. cable off the battery then you will not measure any voltage between the neg. cable and the pos battery because there is no complete circuit back to the neg side of the battery. I would start by making sure that the battery connections are clean and secure, as well as the main connection at the alternator. Check that there is no corrosion on any of the terminals. Use some sandpaper if you need to clean them up, on the terminals and the cable connectors.
Remove the Neg. Cable first, then the + Red cable. Slide up the insulation cover around the battery. Unscrew the battery holding plate on the bottom near the engine. Pull out battery. Drink a beer.
check make sure the neg. cable is tight, check cable for corrision in cable by flexing cable if it hard u need a cable, also check for cable tightness to connector that connects to battery. Did you hook the pos. to neg. and neg. to pos?
disconnect your battery, {neg. cable first} then pos. cable, go under your car/truck and unbolt starter. There you have it. To install work it backwards
neg cable bolted to the body of car.
disconect the neg. battery cable for 25 seconds
Disconnect the neg battery cable for 10 mins.
remove seat, remove neg cable from frame and Pos from battery, remove strap and take out battery.
Attached to neg post on battery should be labelled with (-) sign if not color coded black.
JUST REMOVE THE NEG BATTERY CABLE , THIS WILL RESET THE COMPUTER . LEAVE CABLE OFF FOR 20 SECONDS . PUT NEG CABLE BACK , THEN START CAR , AC SHOULD WORK.