Two questions guys:
1) I am installing an aftermarket gauge cluster (Summit) and have a question on hooking up the voltmeter. I know the dash can be used as a ground or the wire I use to ground the gauge lights, but what line would you recommend tapping into to get my voltage reading? I know I could just stick the lead into the fuse block but that doesn't seem like a great idea. Some people here warned about being downstream of high load devices like the cigarette lighter.

2) What are your thoughts on installing a terminal block at a 12V source to attach any additional accessories? I saw a cheap terminal block (think back panel of a VCR) at Radio shack. I'd use it to hook up an air horn or maybe more lights. Where would be good to tie this in?

Thanks.

 

1) I ran my voltage lead to the battery side of the solenoid

2) Same thing, battery side of the solenoid.....Might want to think about using a relay for the "high draw" stuff

 

I installed an accessory fuse block right next to the original fuse block to power accessories when I installed the power seats in my '78. The block is fed by a 40A relay and 40A fuse. Check out my build thread for pics.
https://www.ford-trucks.com/forums/1...4bt-build.html

 

That would mean that the line is hot all the time, even when the truck is off, right?

 

I'm using an accessory block I got off the rotting carcass of a late 90s Camaro. It's hot all the time but has a cover to protect the post and connectors. EZ.

 

Yes, hot all the time. A fuse would be advisable or you could install a switch, but I don't and I'm yet to have any problems.

 

That is not a good idea. While voltmeters are relatively high impedance and don't draw much current, it will drain the battery over time. You should hook it to switched power; there's no reason not to.

It's also a very bad idea to run unfused power straight from the solenoid all the way into the cab. Depending on the gauge of the wire, the insulation will literally fall off the wiring if it fuses to ground, and smoke everything in its path.

You shouldn't be doing this in your truck, and you definitely should not be recommending that others do it either.

In my '79, I power my voltmeter from the same source as the radio (YELLOW with BLACK stripe). It's hot when the key is in RUN or ACC, and is protected by the fuse panel.

 

Agreed 100% You need a fuse to protect it...........Look at my setup in my build. It provides fused, switched power via a relay which feeds a fuse block so that you can protect each new circuit you add.

 

Thanks for the warning. The suggestion of the radio power source is very good idea, as it was fuse protection (though you can install an inline fuse) and is switched on/off.

 

Lemme clarify my post... my accessory terminal post is mounted on the inner fender near the hood hinge and connects to the load side of a 175A mega fuse. The opposite side of the mega fuse connects to the hot (battery) side of the starter solenoid.... each circuit connected to the accessory terminal post is then protected by a separate fuse.

 

Curious- where can I get a complete wiring diagram for a 1973 truck? I purchase a set of shop manuals online but they lack the wiring diagram.

 

The Haynes manual for these rigs has a wiring diagram. 73s are kinda odd in that the schematic lists it for 74-79 but it's generally the same.