Amp. Gauge Question.

L.Fure

Well-known Member
I can never keep this straight. Which side does the wire from the alternator go to on an amp. gauge. The + side or the - negative side.
 
They can be labeled either way. Most often with the Plus sign marked terminal hooked to the non ground side of a negative ground
system. But there are many exceptions. Jim
 

On a negative ground system the hot wire from alt/gen is supposed to go to the + side. In the real world it sometimes works the other way. Verify you are getting a charge with a Multimeter and hitch the ammeter up to match what it shows.
 
(quoted from post at 15:10:28 02/16/18)
On a negative ground system the hot wire from alt/gen is supposed to go to the + side. In the real world it sometimes works the other way. Verify you are getting a charge with a Multimeter and hitch the ammeter up to match what it shows.

Okay, that makes more sense. I'll tell the whole story in case someone wants to know how I got into this mess. My 300s gauge cluster is a mess. The only things that worked were the oil pressure and amp. gauge. The amp. gauge didn't work like it should though. It would shake back and forth when the engine ran. I decided to install an aluminum plate and gauges like conner1306 had done with his 300RN. After getting everything hooked up like it was on the old gauge cluster I started the engine to see how everything worked. The amp. gauge still shook back and forth like the old one. When I have the engine off with ignition and lights on, the needle on the gauge pulls over to the positive side. I think I have more going on than reversed polarity. The person that had wired this mess used the amp. gauge as a junction box with four wires hooked to it. I'll have to do as you said and trace out each wire with a multimeter to see where they lead to.
 
If your ammeter needle is moving around a lot, you have a problem with the voltage regulator.
Personally, I have started using volt meters to observe charging and the bat condition. I have switched several tractors to 1 wire alternators and the amp meter in the clusters could not handle the out put of them.
Loren
 

I agree with Loren, a voltmeter tells more about the system than a ammeter. the ammeter only shows current flow whereas the voltmeter shows that all the loads are satisfied and battery voltage is being maintained at regulated voltage whereas the ammeter could show a 30 amp charge but the system voltage could be down a volt or two and you would never know it.
 

Okay, I have the amp. gauge working now. There was a hot wire on the negative side from the solenoid, and the battery wire from the alternator was on the positive side. I checked the voltage, after I changed things around, of the battery and it was 14.9 volts and 13.7 volts with the lights on.

On the original gauges the oil pressure was always around 30psi. Now the new gauge reads 10psi at an idle and around 12psi at 1900rpm. I even bled the oil line that attaches to the oil pressure gauge. I'm kind of disappointed with that outcome.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top