a short

I have a 1977 corvette and i am having trouble with a short somewhere

when i turn on the wipers and try to run the heater they will not run unless the door is open on the car and the inside lights come on then the wipers come on and the blower motor comes on.  i can not for the life of me figure out what would do this and can not find the short any ideas from anyone please.

A short blows fuses.  What you seem to have is a wiring error.  Think about this if you had a wire that ran from the battery to all the switches every time you turned something on it would work.  Now if you reversed the wire to the interior lights and made it so the other items only had power when you turned on the interior lights.  Thats what it sounds like you have.  Did this problem just happen or did some one replace something electrical in the car and could have miswired it? If the problem just happened all by itself I think you will find a harness that has melted wires causing this problem.  

i have only had the car 3 1/2 months since then i have had a newmotor put in it but i do rember driving it in the rain one night the week i bought it the wipers worked. After i picked the car up about a week later i turned on the wipers they didnt come on i whent to get out they came on when the door opened. the heater blower didnt comeon when i tryed it when i got the car so iam still searching i have cleaned all wires cant find any bad ones yet.  

Did you check the ground strap that connects the block to the firewall?  

It sounds like who ever put the new motor in probably either didn't hook up some connectors (correctly) or (more likely) crushed a wire bundle or connector while working on the car. I'd go back and complain.

Bogie