so guys I am trying to hook up my new tachometer, however the letters on my fuse box are unreadeable. so I was wondering if anyone had a diagram, or a picture of a fuse box in a 1977 f250 custom that shows what kind of fuses are used and what they control

 

I thought they hooked up at the coil. My 79s coil has a terminal marked ' tach' .That's where i hooked up one on a street rod i have.

 

He still needs + power for the tach. I would use a test light to see what is hot with the key on. Should have my tach in this week.

 

https://www.ford-trucks.com/forums/5...x-diagram.html

They show it in that thread.

 

Here is a scan I posted in another thread. It is from my owners manual for my 77 Custom if your box doesn't match up to the other post:

https://www.ford-trucks.com/forums/1...l#post13171862

 

Even easier:
Keyed power behind instruments

Lights are blue/red

Of course you need a tach lead and a ground
If you use these things, you don't need to cut at all, just crimp on some ring terminals and bullet connectors.

 

Btw when using bullet connectors, the female side is used on the hot or energized side and the male end is downstream.

Why? Because an energized and open male bullet connector can short to ground if left unconnected. Bzzzzt.

 

thanks for all the help! got the tach in and working good!