Oil Pressure Gauge

[75gmck25]

An ammeter gauge with a shunt is designed to measure very small voltage differences between the two sides of the shunt. Since the two fuses are where the gauge connects into the wiring harness, I assume it is measuring the voltage difference between those two points. However, I’d have to take a close look at the wiring diagram to be sure.

 

[Ellie Niner]

An ammeter gauge with a shunt is designed to measure very small voltage differences between the two sides of the shunt. Since the two fuses are where the gauge connects into the wiring harness, I assume it is measuring the voltage difference between those two points. However, I’d have to take a close look at the wiring diagram to be sure.

It actually does measure amperage, but only a small percentage of the current actually flows through the shunt (guessing 1 or 2%). Those fuses are 3 amps, IIRC

 

[Raider L]

@Ellie Niner,

Now that you've explained that, I realize that the reason why my Autometer Amp gauge doesn't work. The instructions show the gauge needs to be connected to a 12 volt source as close to the positive cable (right to the cable actually) with a #10 wire on one post on the back of the gauge, and the other, another #10 wire goes to a 12 volt ingnition source. I guess I could put it into the ignition switch or one of those wires somewhere?

But nooooo, I thought I'll be real brainy and just use the factory wiring, with those two fuses and wiring that goes right to a #10 power wire coming off the battery that is hooked up to the fusible link on the firewall, and have tested every which way from Sunday to try to figure out why the Amp gauge doesn't work. I'm not very good with electrics. Where the wire from the other post on the back of the gauge goes, the way I hooked it up, I don't even remember. I'll have to look for the tenth time and still haven't seen where the wire on the other post goes to. The instructions say, " If the gauge works oppsite, switch connections."

I'm sure it's not connected to a ground, which the instructions are very clear DO NOT CONNECT TO GROUND! For obvious reasons it would instantly melt the Amp gauge. I would love to see that gauge working and it wouldn't take me ten minutes to hook it up correctly, but I'm too lazy to do it, right now that is. I need to extend several ground wires that come from several gauge lamp bulb sockets and will have to pull the instrument panel out in order to extend the panels distance from the dash. I'll have the perfect opportunity, then, to fix the Amp gauge.

 

[Ellie Niner]

@Raider L If it's requiring at least 10ga wire, that's going to be a full current ammeter (probably 60 amp?), so the whole charging system is going to have to flow through it for the gauge to read correctly. I thought you were dealing with stock gauges. You'll have to make some significant wiring changes to run that... basically running the output from your alternator into the cab, through the ammeter, and back out to the main terminal on the starter solenoid. You'll also wanna put a fuse or fusible link in the circuit. I attached a very rough diagram of what you're looking at.

You must be registered for see images attach