Hei I just installed a new alternator in a 773 G series. My lights pulsate now and I am getting 15.9 volts to the battery. I am also getting battery voltage to the alternator via the harness plug ie the lower left terminal when looking at the alternator. this occurs key off, cab raised and unplugged from alternator. voltmeter attached to harness plug. when this is disconnected the terminal on the alternator is dead. Please help with advice or a wiring diagram. thanks
Note that I also checked the error codes and they state None. Key off I have battery voltage on both terminals in the plug that connects to back of alternator.
key OFF you should only have voltage to 1 wire, key ON both wires should be powered up. 15.9v is high, typically you'll see 14.3-14.6 @ idle if the controller see's 16v for approx 15-20 seconds, it should throw a fault code for high alt output, or high battery voltage. where did you get the alt from? :drinkup
The alternator came from a local alternator/starter rebuild shop. it was not a rebuilt but a new unit with a one year warranty. I took out the new one and returned it. he checked the regulator and it was bad. Not sure what caused this to happen. took another new one home and so far all appears ok. 1 wire has battery voltage key off and 2 wires key on. Hope thi solves problem. thanks for getting back to me.
i had a strange feeling there was something wrong with the "new" alternator. :drinkup
I have the same machine 773g and I have alternator issues also I Am getting 11.6volts with machine at idle. So I would say my alternator is shot this correct guys? Or is there something f else I can check?
"key OFF you should only have voltage to 1 wire, key ON both wires should be powered up." that's the first thing to check, then check that the belt is tight enough. Assuming the battery holds a charge when charged up, then you could check the voltage drop on the alternator to battery and battery to ground. Then take it in, or pull it apart yourself.
Checked all the fuses and everything looks good. Checked my voltage on my battery when not running getting 12.4 and checked when machine is at idle getting still 12.4-12.3 no change. Belt is tight just not sure on the wires as there is a wire harness coming off the alternator that is not plugged in to anything and 2 wires also that are not connected to anything but looks like they never were?? Trying to find a wire diagram or something that shows me
What wires ARE connected to the alternator? Does the alternator look original? it could have been replaced with a one wire alternator, sometimes they won't kick in unless they're revved to the max.
I can't say this diagram applies to your 773G machine serial number, but here's a diagram of the alternator wiring on one. Wire 1010 goes to battery terminal on starter, wire 1800 goes to fuse 11 and is powered by the switched power relay in the fuse box. Wire 1800 is the "exciter wire", if it doesn't have a voltage input to the alternator that alternator won't come to life.
Keep in mid that an alternator needs current to energize the field winding. This is a one-way circuit, controlled by a diode - which is nothing more than an electronic check valve. When you have a current "bleed" problem in ANY vehicle with an alternator that diode is probably the gremlin. If I'm reading you right, this is why, when you disconnect the alternator terminal, that you don't have power! Anyway - this is why you're getting voltage in that terminal plug with it disconnected. It's the diode (IE: electronic check valve) that keeps current from flowing THROUGH the alternator and into your electrical system, when the machine isn't running . Hence the current draw!!! The way I check a charging system is this.............remove your negative battery cable when the machine is running . If it stays running the alternator IS charging, because you just removed the battery from the charging system! If the machine dies, the alternator isn't charging. But that diode can still be bad and. The only way to determine this 9that I know of) is to have the battery checked. If the battery is good the diode is junk. We used to replace just the diodes in alternators when I was much younger. Now they all want to screw you, by selling you a new one!!!