Aftermarket Tach Install Fail

[Bearhawg]

What could I have touched in these three areas that would have caused my system to stop charging? I installed a small aftermarket tach with a very simple setup. Green tach wire, red power wire, white dial lighting wire and a black ground wire. Easy-peasy. I secured the tach to the column with big zip ties. I know nothing about chasing electrical gremlins.I removed everything and through the tach in the "I'll do it later" drawer. I'm thinking about starting my rewiring project six months early to solve this.

Any suggestions? Thanks!

Fuse panel where I tapped into the switched power (radio fuse) and dash light fuse and tried to attach the ground wire on the horn relay mounting screw. I ended up using a screw on the bracket used to hold the column in place at the firewall.


The HEI distributor where I tapped into the tach connecter


The ratty engine harness where I wrapped two frayed wires (yellow and green) that I found in the process.

[Shinysideup]

What amperage does that tinfoil fuse blow at?

Also, your new issue is the alternator? What voltage running and at rest?

[Bearhawg]

Originally Posted by Shinysideup

What amperage does that tinfoil fuse blow at?

Also, your new issue is the alternator? What voltage running and at rest?

You have an excellent point about the tinfoil. The PO installed and I honestly I’ve been afraid to touch it. How do you test the alternator output. I have a multimeter. Will that work? I’m new to all of this and everything is a learning opportunity. Thanks for the input. I need all the help I can get.

[Shinysideup]

Ok, how do you know its not charging?
Simply test battery voltage engine off and then running, at the battery terminals. Should be 12.5, then 13.5-14.5 running.

As for the tinfoil, replace it with correct size fuse for that circuit. That could burn down the truck if wires overheat with no fuse.

[saxart]

Originally Posted by Shinysideup

What amperage does that tinfoil fuse blow at?

That looks like 15amp tin-foil to me.

[rpmerf]

[jcwren]

What's that heavy red wire with the black connector in the first picture go to under the hood? I've got one of those, but it's not connected to anything, and it doesn't show up on the schematics.

I'm thinking MAYBE the guy who started restoring the truck added it for an electric choke, but I'm not certain.

[Bearhawg]

Originally Posted by jcwren

What's that heavy red wire with the black connector in the first picture go to under the hood? I've got one of those, but it's not connected to anything, and it doesn't show up on the schematics.

I'm thinking MAYBE the guy who started restoring the truck added it for an electric choke, but I'm not certain.

Believe it or not that goes to an intermittent wiper control on the dash. I’m sure it worked for about 30 seconds after it was installed. There is a power port (BAT) on the HEI distributor that I tapped for my electric choke conversion.