1981 Mustang Hatchback ????'s

I'm looking at an '81 hatchback, and there is a switch inside the car under the dash that says 'amp pull'. I've seen it on a '79 also. Does anyone know what this switch is for??!!

I also own a '91 4cyl that is having trouble. The car will not turn over. It will sir there and try to crank all day long but just won't turn over. I've replaced the fuel pump, checked the distributor to see if the timing was off, new spark plugs and wires; just can't figure out why it won't turn over. So if any body might know what wrong and how to fix it i'd appreciate it.

If it's the switch I'm thinking of, it turns on the amp for the premium sound system. It was integrated into the radio in '85.

I also own a '91 4cyl that is having trouble. The car will not turn over. It will sir there and try to crank all day long but just won't turn over. I've replaced the fuel pump, checked the distributor to see if the timing was off, new spark plugs and wires; just can't figure out why it won't turn over. So if any body might know what wrong and how to fix it i'd appreciate it.

How did you check the timing if it wont run?

Sorry I didn't mean timing, I meant I changed out the distributor caps and all that junk.

I'll check and see if it goes to the sound system. I mean the car doesn't have a radio(head unit) but i'll check and see how speakers it has and if would be considered a 'Premium' sound system.
If theres any other ideas out there please let me know.

Sorry I didn't mean timing, I meant I changed out the distributor caps and all that junk.

The speakers have the word "premium" marked on them for the premium sound system. A '79 Premium sound system by todays standrds would be pretty lame anyway.