I'm not electically savy by any means so if some one can help please do. I'm installing an aftermarket ECU and the for the fan and fuel pump the harness comes equipped with a dedicated relay and a fuse and a wire marked positive(+) for each. So am I to just hook the positive wire to the fan/fuel pump ( should I put a ground wire too) and be done with it. Or is there more to it. Also with a 12V+ switch wire (needs 12V when the key is in the on and run position) what would/where be the best way to hook it up.

 

You will most likely need to run a ground as well to make everything work. The ECU only care abouts what's on the positive side though so that's why that's all you got but you will need grounds.

For switched power, you can get under the drivers side panels and find one from the ignition switch harness (on top of the steering column). However, the easiest place would probably be from the factory radio harness. There's also a switched power wire there. It should be the yellow wire. You can just use a test light to test it with the key in run and if it lights up then test it with the key off and make sure it doesn't light up.

 

I wouldn't tap into the radio wire harness. Especially if you have 2 or 3 items that need a power source and it would be too much of an excessive draw on the radio wire which I believe is only an 16 or 18 gauge wire.. I would be more likely to say that it would be safer to put a spade blade on + wires and plug into the ACC fuse block..
I believe there are 2 spots in the fuse block for ACC to be plugged in. Just a suggestion.