74 Duster Electric problems

You don't need much in the way of testers, but you do need a few things, and it'll cost you about 50 bucks total

Either go to an auto parts store and buy a 12V test lamp or MAKE one. If you are really strapped for cash, this is not difficult to do LOTS of ways to make one, depending on what you have for parts lying around. Something like an old tail lamp socket or dome light will work

Go to radio shack and buy a couple of bags of their clip leads, one of the "large size" leads, and one of the smaller size cllip leads

Look over their test meters (digital multimeter) and seriously consider buying one.

BUT you can do a LOT so far as basic lighting and fuses with just a test lamp

For example, take the kick panel apart and find the connector in the harness where the harness comes forward out from under the door sill and connects with the dash harness.

DISCONNECT that connector temporarily, and see if that stops the fuse blowing. If so, take a GOOD look at that rear harness and the sockets.

It's a few minutes to yank the door sill plate off, pull the rear seat, and access the harness, and inspect it for cuts and damage.

The other thing you REALLY need is to get a factory shop manual. You can buy these several places on the internet on CD, some as low as 30 bucks or so.

There are "usable" diagrams here, but believe me, there are mistakes, and a lot missing so far as accessories

http://www.mymopar.com/downloads/1974/74ValiantA.jpg

http://www.mymopar.com/downloads/1974/74ValiantB.jpg

Another thing that can cause blown fuses IS THE FUSE BOX ITSELF. These cars are getting old, things deteriorate. If the fuse holder clips get loose connections, or rusty/ corroded, and don't make good tight connections to the fuse, they HEAT UP. And heat blows the fuse!!!

So you want to take a sideways look at the fuse panel.

Post back here and we'll help walk you through some tests