Fuse sizes

[my67c20]

Well i have searched found the color wiring diagrams reviewed them and now have fuse questions. This is a 67c20.

From the firewall i have 3 wires that previously were all hooked together with no fuses. I have a black (B), a black with white stripe (BW) and a red one(R). The BW has a thingy on it (pictured). What is it and can it be replaced with a new style fuse? The R wire splits off and goes to the alternator (converted to internal regulator). By the color schematic i should have a fuse or fusible link in various locations. Can someone tell me what should be at F1, F2 and F3 as well as there values (per my sketch). Should anything be hooked up to the unsued spot on the starter? (sketch is viewed from the front). At the point were i can turn the key and try to strart this beast but do not want to watch it burn up before i can road test it. Thanks

[john]

The black/white is a ammeter wire. Should have a 4 amp fuse. There is also a black one on the other side of the radiator support for the ammeter 4amp also.

[my67c20]

Thanks John. So am i too assume that little black thing is actually a fuse holder? I tried to open it but no luck. So it looks like some nip and tuck. What about the other wires? Is the black wire potentially the other wire for the ammeter?

[LockDoc]

-
The black/white wire is ammeter wire as John said and it ties into the red 12ga wire from the alternator and goes to the instrument cluster plug (position 1). The black wire (actually black/brown) comes from the junction block located on the inside of the fender by the battery and also goes to the instrument cluster plug (position 12). These two wires are only used with the gauge clusters. Idiot light clusters don't have them... Anyone that is changing from light cluster to gauge cluster will have to add them.

The black rubber bulbs are fuse holders for 4 amp fuses. they just pull apart but don't bend them or you will break the fuses. I see no reason they couldn't be replaced with newer style holders.

LockDoc

[my67c20]

Well i gues that explains the cracking sound when i was fighting to open that thing. What sizes should the fusible links be? So F2 and F3 should be a 4amp. I will have to look at that black wire, but pretty sure it might be black / brown. Thanks

[storm9c1]

The rule of thumb for fusible links is 2 wire gauge sizes smaller. So if you have a 14ga wire, you would want to put a 18ga fuse link in there. In some higher current applications, you can go with 1 wire size smaller. But the recommended practice is 2. It is best to buy fusible link wire and fiberglass sleeving to cover it for best safety. But I have made my own fusible links (using a wire with a insulation of 120 deg C or better) and covering the wire with a length of shrink tubing for added protection from burn-through. It should be about 3-4" long, sometimes longer with higher-current applications. I recommend soldering the connections.