Well, I was trying to keep everything short, but here's all what I did... It is a two wire alternator, both wires go straight to the reg, I was hoping someone could tell me how to check the voltage at the alternator, between the two wires or from ground to each one? ( it's not like an auto alternator). I have taken the alternator off twice in two years and took it to an alternator shop where they said it was good. Both times I then installed a new reg, and the first time everything worked fine, this time still nothing. 12.4 volts at battery, running or not. Battery is new. I have electrical schematic, but don't know where to check for voltage. Both old reg.s I took off had melted plastic coming out of them. My wife told me the glow plug light stayed on one time and she had to turn the switch off and then back on? Don't know if that has anything to do with it not charging tho. Also, noticed plastic connector going to alt. is disinagrated Looks like it is still connected, but will put new one on tomorrow. So that's all I have done so far.
TC18 quit charging
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LD1
Epic Contributor
Any chance you can post up a pic of the schematic? Either scan and post or take a good pic and upload?
If I had to guess, on wire needs 12v going TO it with key on to energize the field. Second wire back to reg with juice out.
If I had to guess, on wire needs 12v going TO it with key on to energize the field. Second wire back to reg with juice out.
guyw
Silver Member
Here are the pages from the manual on trouble shooting the charging system.
That's kinda what I was thinking but wasn't sure with this alt? I checked the two wires going to the alt. Yesterday while tractor was running and one has 11.3 volts going to it and the other is 0v. I'm guessing the alt. Is not putting out, but now I'm wondering if the alt. Shop I took it to, maybe didn't know how to check that alt and just told me it was good. They told told me as long as it has that magnetic resistance when you spin it, it was good?
guyw
Silver Member
Any progress or resolution with the charging problem?
Replaced connectors at alt. still nothing. I'm not getting any voltage out of alt. measuring between the two terminals, and only getting 11v to alt on one wire to ground. Going to jumper a wire straight from charged battery to alt and
See if it starts to charge?
Last edited:
guyw
Silver Member
I don't think I would do that. The alternator is supposed to supply a minimum of 28 Volts AC. The AC voltage needs to be rectified and regulated to the 14-15 Volts DC to charge the battery. It is not a generator, but a 2 wire alternator that just supplies the AC voltage to the rest of the circuit. Connecting it directly to the battery could produce very bad results.
CCWKen
Veteran Member
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You may have some toasted wiring from the glow plug incident. I would be checking the wiring harness for damage and metering end to end continuity and for shorts of all the wires in that harness. If you keep cooking regulators, it doesn't make sense to keep replacing it and expecting a different outcome. That's the definition of insane. 
Forgot to mention: Your alternator outputs AC until it gets through the rectifier/regulator. If you have your meter set to check DC voltage, your readings are bumpkins.
Forgot to mention: Your alternator outputs AC until it gets through the rectifier/regulator. If you have your meter set to check DC voltage, your readings are bumpkins.
