[Didge]

I have a 67 chevelle. The owner before put a speedometer with the gauges on each side in it. All of the gauges work except the AMP guage. I got underneath the dash this weekend and found out that it is not hooked up. It has two connectors on it. Can anyone tell me where I need to run wires to get it working ? Also what guage of wire should I use ?
Thanks,
Greg

 

[SSuper Dave]

Forget the amp gage and get a volt gage instead. The readings it supplies are more relevant and its a lot less hassle to hook up and has much less potential for problems. SSuper Dave

 

[Cameano]

Didge, SSDave has a point. The amp guage avails itself to high amperage running under the dash, and the potential for fire, if there's a short due to abrasions of a carelessly run wire. If the original wiring is there, check it for grounds first, before hooking it up. Basically, the amp guage hooks up to a shunt located close to the battery. It is a small plastic block, running from the positive side of the battery, to the block, to the amp guage, back from the amp guage, to the alternator. All of this wiring carries the amperage the alternator is putting out. The guage measures this. Modern day cars use voltage guages due to their simplicity. They can tap in almost anywhere in the electrical system, as they only measure the voltage. They do not need a dedicated path to work. Thus, you eliminate excess wiring carrying high amperage. You can run the amp guage, if your goal is to restore the car, just be careful you try to duplicate the factory wire routing, so it doesn't have a chance on chafing on sharp edges, and short out, or worse, start a fire. Otherwise, I'd go with an aftermarket voltage guage, if you feel you need one. On the amp guage, use a 10 guage wire, with soldered connections, and shrink wrap, to ensure it won't give you charging problems, as the alternator output travels through the guage first, before it charges the battery. Good luck, Darren

[This message has been edited by Cameano (edited 10-16-98).]

[This message has been edited by Cameano (edited 10-16-98).]

 

[Didge]

Thanks,
After what you have said I should be very carefull of running the wire. You mentioned from battery to gauge to altenator. So that would connect to the red wire on the altenator, right???
I am just trying to utilize the gauge that is in my dash. It just shows "C" on top and "D". Can I use this as a voltage guage instead ?
Thanks again,
Greg

 

[Chuck]

Be very careful and reread the directions above. A shunt is a path around the regular path. A shunt allows the main path to go its normal way and only samples the current in the path. I'd get the manual on the car from Year One or another supplier and look for a guage dash setup so you can visualize what is going on. I immagine that you can not replace the amp guage with a voltage guage since it is part of the speedo. Good luck

 

[Bryan]

I believe- and I could be wrong - that there are two ways to wire an amp guage. I won't attempt to diagram them, but basically one way measures what the alternator is putting out (sounds like the way described above); and what I think is the factory way, which measures what's coming from OR going to the battery. Does this sound correct to anybody else out there? Bryan

 

[tom 2]

The amp gauge has to "see" all the current flowing to and from the battery to of any use at all. The only current not directed through the amp gauge is the starter current. This requires big wiring to and from the gauge in the dash which is pretty impractical, which is why voltage gauges are the norm nowadays. If you want to wire up the amp gauge, you'll have to sort out the wiring and run about a 10 gauge wire to and from the gauge. Main wire to battery on one terminal, all other circuits wired in to the other terminal. You can probably cut open the wire looms across the radiator support and trace the original wires down for this. Might not be that bad a job if the original harness had provisions for the amp gauge. tom

 

[Wes V]

Didge;

Assuming that it's a name brand gauge, go to your friendly auto parts store and ask to see (or zerox) the instructions. You could always write,or call, the manufacturer. This way, you know that it's hooked up as it should be.

I agree with the prior posts in regards to the safety in using an amp meter. Electrical shorts are NO fun! (BTDT)

The only advantage in my mind in using an amp meter over a volt meter is that you can get an immediate indication of a problem. Of course, that's if you keep looking at the think. The real easy solution is to retain the alternator "idiot" light.

One reason for keeping the idiot light is that it will grab your attention once a problem occurs! A real good idea!

Wes.

 

[RobertD]

I've seen many problems with the after market amp. gauges. Sounds like the last owner knew what he was doing just leaving it not hook up. Agree with eveyone, voltage meter would be better.

 

[JERRY66SS]

If you have the factory ammeter, a wire goes from the top terminal of the ammeter to the horn relay. The bottom terminal goes to the junction block (positive) nearest the battery. Both wires are 20 gauge from the ammeter to the firewall connector. In the engine compartment both wires are 14 gauge from the firewall connector to the relay and block. This is the way the factory did it. Jerry

 

[Fred Ont canada]

Dont forget guys both amp gauge and volt meter have 12volts running to them, any short in each setup will cause a fire...FRED