fusible link vs. inline fuse
 

Got a "lingo" problem. I have 2 wires that I think are giving me trouble after I crossed some stuff up and made some smoke donations to the atmosphere. 1980 F150 by the way. The first pic we will call "A" (Red/Black) and the second we will call "B" (Red/White inline thing). Can I replace "B" with "A"? Or "A" with "B"? Whats the diff. between the 2? Whats the diff between a fusible link and inline fuse? The reason I ask is because I think one of them is fried and I have no power/no startup in the truck. They are both off the right side of the starter solenoid.

http://rsk.imageg.net/graphics/produ...266425w345.jpg

http://rsk.imageg.net/graphics/produ...265101w345.jpg

I think my knowledge is decreasing. I feel dumber and dumber every day. This seems like I should understand this so easily, but I just feel dumb right now. I guess a 1980 f150 needing constant maintenance wasn't the right choice.

If you think the inline fuse might be fried, just twist it to unlock it and take out the fuse and look at it. To check the fusible link, I think (which is dangerous) that you check to see if it is flexible. If not, it is fried. Someone may well correct me on this one. I know that you can also check with a meter and probe to see if you are getting voltage on both sides of the link.

With a fusible link you check for voltage on either side of the link. A fusible link is a piece of wire that is smaller than the wiring in that circuit. When the current draw is too high the wire burns up and opens the circuit.

Both of the pictures you posted are fuse holders.

Those are aftermarket fuse holders, they just use different types of fuses, so you can interchange them. They were probably added to run some accessories and have no effect on the truck running, but its possible that someone replaced the fusible links with regular fuses. To check the fusible links pull on them and see if they're stretchy, the wire inside burns in 2 and leaves the insulation looking ok.

update!
 

Cut these three bad looking wires from the solenoid. They all three have some sort of fuse attached. Could these be the problem looking at the pic?

https://mail.google.com/mail/?ui=2&i...disp=inline&zw

pic doesnt work

Can't see a pic, but if the smaller wires on the battery side of solenoid are looking burned, that would most likely be where your problem is.
They can be replaced with regular fuses, in a pinch. A regular fuse will blow much quicker than a fuse link, so it could cut the power when you turn on an accessory. A fuse link is designed to work like a "slow blow" fuse, and a short term spike in current won't cause them to pop, unlike a standard fuse.

You can get replacement fuse links at most autopart stores. Factory color is listed.

1: Altenator to Battery Fuse Link (off starter solenoid): Black/Orange stripe: 16 gauge

2: Main power feed fuse link to Headlamp switch and fuse panel (on fender with gauges, off starter solenoid with idiot lamps: Orange: 16 gauge

3: Main power feed fuse link for ignition switch: (on fender with gauges, off starter solenoid with idiot lamps: Dark Green: 16 gauge

4: Altenator to Electric Choke: Inline (White/Black) : 20 Gauge

I think the problem is terminology. Both pictures in your OP are of inline fuses, just different styles. You do NOT want to replace a fusible link with an inline fuse. Like MisterCMK said, a fusible link is a section of smaller diameter wire. Its factory designed to burn up like a fuse is, but unlike a fuse, will allow a higher amerage through for a set period of time (period of time is dependant how much more amperage is going through it...), rather than burning out the instant there is a surge. You don't want to just cut and solder a fusible link back together, as it is then the wrong length and won't burn out, possibly damaging other parts of your electronics.