67-72 fuse block explanation

[casper1969]

Hello all, first off I tried to search for a thread on this and didn't have much luck. so here I am
my 1969 gmc fuse block, the 2 spades labeled ign, unfused has a 30amp fuse/relay plugged in there...all pictures i've seen of other blocks either have nothing or wires plugged in there...what's going on with mine? any help would be greatly appreciated i'm not electrically talented

[LockDoc]

Originally Posted by casper1969

Hello all, first off I tried to search for a thread on this and didn't have much luck. so here I am
my 1969 gmc fuse block, the 2 spades labeled ign, unfused has a 30amp fuse/relay plugged in there...all pictures i've seen of other blocks either have nothing or wires plugged in there...what's going on with mine? any help would be greatly appreciated i'm not electrically talented

That would be something that someone has added. Where does the wire from the 30 amp fuse/relay go?

LockDoc

[casper1969]

I am not sure I do know it's upgraded to HEI and something hasn't quite been right
Since I've owned it my after market tach never works correctly

[LockDoc]

Originally Posted by casper1969

I am not sure I do know it's upgraded to HEI and something hasn't quite been right
Since I've owned it my after market tach never works correctly

You need to follow the wire and see where it goes. If it is for the tach or HEI I don't think you want a fuse in the circuit. You also want to make sure that the HEI is getting a full 12 volts and the lead is not from the resistance wire for the old points distributor.... If they used that wire you would only be getting 6-8 volts to the HEI.

LockDoc

[casper1969]

LockDoc, you are correct, ignition wire back fed through the fuse and dist, powered from the original yellow wire, what a mess the PO made
i'm surprised i never had an electrical fire. I certainly know why i had lack of power now. Thank you so much

[LockDoc]

Originally Posted by casper1969

LockDoc, you are correct, ignition wire back fed through the fuse and dist, powered from the original yellow wire, what a mess the PO made
i'm surprised i never had an electrical fire. I certainly know why i had lack of power now. Thank you so much

No problem, glad it was an easy fix....

LockDoc

[bigK76]

My question may be already answered but what year chevy pickup can I get blade style fuse block out of to work on my 1969 c10

[El Dorado Jim]

Originally Posted by bigK76

My question may be already answered but what year chevy pickup can I get blade style fuse block out of to work on my 1969 c10

would like to know also

[ray_mcavoy]

Originally Posted by bigK76

My question may be already answered but what year chevy pickup can I get blade style fuse block out of to work on my 1969 c10

I believe it was during the later part of the 1978 model year when GM started using the ATO/ATC (blade style) fuse boxes in their trucks. However, the fuse box is somewhat integrated into the cab harness (lots of wires crimp directly to the fuse contact terminals). And a 79+ cab harness isn't going to be anywhere near a direct swap into a 67-72 truck. So you're basically looking at cutting & splicing all the wires that connect to the fuse box.

One option that would eliminate the need for making butt splices in all the wires would be to purchase some new Packard/Delphi Pack-Con III terminals & bussbars that fit the 79+ style fuse box. That would allow you to crimp the wires that were cut away from the old 67-72 fuse box directly to the new terminals, which would then replace the old terminals that you would have to extract from the 79+ box. In other words, you would only be re-using the plastic shell/housing portion of the 79+ box.

Another option to look into would be American Autowire's Classic Update kits. These are complete replacement wiring harnesses that feature a number of updates as compared to reproduction harnesses. One of the updates is an ATO/ATC (blade style) fuse box designed to mount in the factory location.

[bigK76]

Thanks I found one in a 1981 C10 that worked perfect I just put in need plugs and worked great.