I'm pretty lame when it comes to electricity. I would like to set up an ampmeter in conjuction with my voltmer that is factory in dash. I'm kinda frightened about frying my wires if I do it wrong and the instuction sheet that came with the meter isn't helping me at all. If anyone has done this on a 77 I would appreciate some instructions on the setup.

 

The amp gauge is conected to the red wire going to your alternator you wire it like cut the wire and install one wire to one term. and the other wire to the other term.Then when you stert the eng. if it shows discharge you reverse the wires Hope this makes sense

 

Since you will be running it into the cabin use 10 gauge stranded wire. Use crimp on insulated terminal lugs for the connections to the amp meter. I also tightly tape the connector with electrical tape as an added safety factor.

 

Let me get this straight. I have 3 wire sites to the alternator.
1. the doudle wire that plugs into the top (red & white wire I think).
2. The larger single red wire that is held on by a nut and has a rubber boot cover.
3. The ground wire (black) that is bolted into the alternator closest to the exhaust header.
So I would run 1 wire to the big red wire that has the boot cover and the other goes where?
I once grounded out the big red wire when a screwdriver hit it and it was a spark than smoke show that fried the inline fuse to the starter. Thats why I'm paranoid about messing with this thing.

 

Try to think of the red wire being a hose . the amps flow out of the alt. into the ampmeter then out of the ampmeter to your batt.

 

Your last posts question. FIRST, DISCONECT THE BATTERY AT THE NEGATIVE TERMINAL. The explainations of what this gauge does and where to hook it up are correct. Here is a small procedure.

The large red wire on the back of the alternator is the one that you want. The easiest way is to mount the ammeter gauge in the car, connect up the two red wires to the back, then run two lengths of red (signifyies hot) #10 wire from the cabin to the alternator with about 6-10" of slack. Tie wrap the wires at the back of the gauge and as you are running them for a neat appearace.

Remove the red alternator wire and hook one of your new wires to the alternator with a soldered on ring terminal like what is on the alternator. Make sure it is an insulated one. Cut back the alternator wire about 6" and hook the other new wire to this one. Strip back the nwires about 1" and twist them together clockwise and connect them together with a wire nut (turns on like a nut). Tape up the connection with electrical tape and that's it. Reconnect the battery and start the car. If the gauge shows a discharge, shut down, disconnect the battery again, and reverse the connections at the gauge. When you start it it should now show a charge.

QUESTION - I missed why you are doing this? Is the ammeter in the car not working or you just want something different?

 

Bigvette1
So I am basically running all the leads from the gauge to that one wire lead. Okay I got it.
To answer your question I do have a voltmeter in dash and I'm haveing some issues with battery discharging. (slow discharge that averages 1 battery/year)I'm not 100% sure of the voltmeters accuracy but would like an amp reading also. I believe my dash lights or headlamp switch may be the problem. Voltmeter drops to far on the negative side when dashlights are turned on. I did the battery check with a light to the disconnected negative cable and no drain was found. So the voltmeter gauge is the only thing I'm relieing on for a drain check. Also I had this voltmeter laying around for a few years in a closed case.
Thanks for all the help guys.. :)

 

I dont know why you want an amp meter, they are useless that is why they stopped installing those suckers in cars ages ago. all you need is a volt meter. If your volt meter reads above 13.5 volts that will show that the charging system is running perfectly. "0"

 

If the nature of your problem is battery drain - that is not an uncommon problem in a Vette. You don't need to install another gauge to chase down the problem. 73-454 is right, another ammeter will not show anything. Installing a voltmeter will only confirm battery voltage. Wait! There are two alternatives to look at.

1. Go to Radio Shack and get a digital VOM. (about $20) Look between battery ground and frame ground with everything turned off. If you read more than .05mv then you have a ground leak that could be anywhere in the car. To find it you will have to pull one fuse at a time with the meter connected. It the drain goes to virtually zero that is the circuit that is the problem. If not, put the fuse back in and go to the next fuse. This is a PITA because of fuse location and chasing it down. You will have to get a Vette repair manual with the wiring diagrams for your car. It will most likely be an old frayed wire that has a minute short to ground.

2. A good workaround is to install a ground interupter at the negative terminal of the battery. It basically unscrews and disconnects the ground from the car when you shut it off for overnight or a couple of days. They sell them at most parts stores and are very easy to install. If you have a digital radio and don't want to lose your radio presets, bypass the disconnect with a fuse holder and about a 1/2 amp fuse. You may still get some battery drain but won't lose ground to the radio.

Another thing to check out is that you are not cooking the batteries. Mayby you are overcharging from the alternator. Put the digital VOM across athe battery when the car is running. A good alternator and internal regulator should be betwen 13.8 to 14.5vdc. More than this and you will consistantly overcharge and cook the battery.

Check things out before you install extra gauges and get into wire cutting.