Fuseable Link Blowing?

[85fr16]

What would cause the fuseable link to blow?
I replaced it with a 20A inline fuse and the truck started and ran but after a 15 min. drive I checked the fuse and it was blown and the truck would not restart till I changed it. I am sure that is not a big enough fuse but I wanted to play it safe.
Any ideas?

 

[Pin_Head]

Which link? I Think there are 3 on an '83.

No matter, because what is causing it is a big time short. Find the short and fix it. Basicall, you start pulling fuses and disconnecting things until you disconnect something and the short goes away; then you found where the short is.

 

[85fr16]

It is the black one coming off the + battery cable.

 

[Pin_Head]

The black circuit goes to the ignition switch and it runs everything that works when the switch is on. Since the link blows rather than a fuse, you can be pretty sure that the short is between the battery and the fuse block. It goes battery to the switch and the switch to the fuse block. Look for wires that have worn insulation or a shorted switch.

 

[desertpat]

Higher Amps

85FR16,
I think a 20 amp fuse can be expected to blow in any of the fusable link circuits on a late model 40. A tad bit low as per my source.

Not to highjack your thread, but did you connect your ampmeter stratling the inline fuse where it used to be on either side of the fusable link?

Also, I would like to ask anyone who knows where I can get replacement fusable link stock without buying a long roll of it.
Thanks all.

 

[bsevans]

85FR16,
I think a 20 amp fuse can be expected to blow in any of the fusable link circuits on a late model 40. A tad bit low as per my source.

Not to highjack your thread, but did you connect your ampmeter stratling the inline fuse where it used to be on either side of the fusable link?

Also, I would like to ask anyone who knows where I can get replacement fusable link stock without buying a long roll of it.
Thanks all.

Do a search on fusible link wire and you will find any number of sites like the one listed below.
The fusible link wire should be 4 gauges smaller than the harness wire it is attached to.
Fusible Link Wire

 

[85fr16]

I think it was the clock, it was blinking and I disconected it and my 20A fuse is still holding
Is it ok to leave the 20A fuse in place of the fuseable link? Is 20A enough or would a 25 or 30 be safe?.

 

[Pin_Head]

No, it is not safe. 20A is way too low and fuses blow too quickly. If it blows while you are driving, everything shuts off and you could have an accident.

The clock doesn't sound like it would be the problem. They blink when the pwer is cut and they need to be reset. It is downstream from a fuse and if it was shorted, the fuse would blow rather than the link. The short may be intermittent. Keep digging and at least verify visually (by unwrapping the wire bundle if necessary and checking the wire) that there are no shorts from the battery to the ignition switch and from the switch to the fuse block. The switch itself could be shorted internally.

 

[85fr16]

It also seems like the battery is getting drained when the truck sits for a few days, do you think this is comected to the fuseable link problem?

 

[Pin_Head]

It wouldn't be surprising if it drained the battery as it is a short. This would also tend to indicate that it is either before or at the ignition switch.