I bought this great '70 88 a few months ago and everything was working fine. But I did notice there were two wires that weren't connected in the engine compartment.

1.) Can anyone tell me what the 2x3" electrical box is above the drivers side fender well?
2.) How about this red/blk wire that looks like it was purposely cut and the ends tied off?
3.) And lastly what about the wire with the inline fuse (what size fuse is suppose to be in there)?

 

looks like the horn relay. gm used them as juction point for power

 

The fuse holder goes to the high speed blower relay on the firewall. I'd bet you do not have high speed right? I forget the amperage of the fuse but it is a real short glass one.

 

20 amp

 

you're right the highest blower setting doesn't work.

two out of three things identified!

 

I thought it was a 30-Amp slow-blow (of an annoyingly small physical size).

Regardless, when it comes to fuses you should be looking in your chassis service manual or owner's manual, not asking random people on the internet. Wanna start a fire?

 

I see the big black joint on the Fusible Link circled as well... Usually the FL is a very flexible piece about 6" long from the junction to a big black "growth" which is the insulated joint to the regular wire that feeds the car. If there is a problem such as a short circuit, the Fusible Link will burn apart and save the rest of the wiring from turning into a heater/ fire starter. They very rarely require attention, in my experience.