this have been covered a thousand times but my ammeter does not work!! this is on a 68 rs/ss 393 turbo 400. i have followed the test procedures in chevy chassis service manual , i put a test light from a ground to term. conn. 4 and the test light came on. so i went to step 2 which calls for going between connector "f" and "4" terminale. this is where i get lost. the picture shows going between "f" and "4" on the connector.which is right?? i am on my third regulator and nothing is working yet. i have been reading threads, post. and stickes all day but have not figured it out yet. thanks for your help.

I'm confused too.... are we talking about the GEN light, or the optional ammeter in the console?

The console ammeter is not wired thru the regulator, the gen light is.

console ammeter. i am reading a paragraph that states amm. equi. veh. use the same initial field excitations and control circuits as the indicator lamp except the lamp is omitted. the continuity test on both types of veh. can be made as follows" am i barking up the wrong tree??

where i am getting my info. is from the 1968 chassis service manual.section 6y-13. big bold lettering " if lamp fails to glow or ammeter fails to function the possible causes are"

Ammeter wiring is TOTALLY separate from the charging system and completely different than the idiot light circuit.

Assuming the charging system is functioning, right?

The is a 14 guage black wire attached to one of the screws on the horn relay, it runs thru the harness into pin BS of the bulkhead connector then pin 8 of the console harness connector to one lug of the ammeter. The other lug of the ammeter is a 14 guage black / white stripe wire, to pin 7 of the console connector, pin AS of the bulkhead connector, then over to the lil junction block on the rad shroud, behind (in front of??) the battery.

Be advised that typically this guage doesn't "do" a whole lot even when it works, though it should move a bunch if you turn the headlights on with the motor off.

thanks a bunch. sounds like this will work. you guys are best

If the ammeter is messed up, consider upgrading to a voltmeter instead.

thanks for the info. look out voltmeter here i come.

JimM! You sound like the 'Man'. Would you be willing to explain 69 Camaro console gauge ammeters? I was digging into mine last summer to add a supplemental wire to carry a larger current flow. That's when I found that the gauge uses two micro wires as-in 'bus'. I don't know if the wires are connected to each end of a long 'charge' cable or a bus. The guage works great. And 30 years ago I took out the Ralley Sport clock and installed a voltmeter there. It works even better than the ammeter.:p (the clock's in the memory-parts box)

Fred, it's been awhile since it's been discussed, so I'll give it a whirl again.

Note that while I am a US Navy trained electronics tech, everything I know about these guages I learned here, mostly from Mark Canning.

First, there is no such thing as an ammeter. They don't exist, period. Meters read voltage. Ammeter's read the voltage drop across a calibrated resistance, with the meters in SERIES with the load and the scale printed to read amps. (Note that "voltmeters" are always installed in parallel)

There's 2 kinds of non-existant ammeters, internal shunt and external shunt (note that shunt is a fancy way to say "resister")

Most aftermarket ammeters are internal shunt devices. You have to cut the main wire to the battery and run the wires into the dash to connect the load in "SERIES" with the meter. This kind of setup is kinda dangerous, running full battery power into the interior of the car and back out.

Chevy used an "external shunt" ammeter in the camaro. The "shunt" (remember, that is the resistance that the meter reads the voltage drop across to determine the AMPS) is the charge wire running from the junction block behind the battery over to the main splice by the horn relay. The meter is connected in parallel with this wire, with one lead to the junction block by the battery and the other to the main splice. If you're not familiar with the main splice, check the "What it is, Where it is" sticky in electrical for a picture and explaination.

Also, while it would be great to switch to a voltmeter, I don't think this is an option for those with factory console guages, no one makes one.

And yes Fred, upsizing that charge wire will throw off the ammeter's reading, because it's resistance will be lower.

I love this web site! Thanks Jim. Shunt is the word I was looking for. Sorry about 'ballast'.
And because of your explanation I know I didn't mess up my ammeter. I hooked up a large wire from the junction block to the battery cable post of the starter motor. (the batteries are in the trunk)
One thing; I'm not following you about 'no such thing as a volt meter for these cars'. Just a minute, I'm going back to read what you wrote,,,,,,,,. OK, I put the meter front and center between the speedo and tach, where the RS clock used to be. And there's, no doubt, a good reason for voltmeters not being made for the console. Who would do that to classic stuff? Thanks again for the scoop!