W400 keeps burning up alternators in Technical IH Talk Posted June 6 I would suggest doing circut resistance tests on both the + side and - side of the circut . It is a pretty simple test . Take a volt meter I prefer a digital one but an analog will work . Positive side : Place 1 lead on the output terminal of the alternator and the other directly to the + post of the battery . Start the tractor and check what the meter reads . It should not read more than .5 volts and preferably less than .5 volts . If it reads more than that that tells you that the electricity finds it easier to go thru your meter leads than thru the wire which indicates that there is high resistance in the output circut between your alternator and your battery . You have your sensing wire hooked up to the output stud on alternator which is fine but it is sesnsing the voltage drop due to circut resistance which kicks the alternator up to try to overcome it and the alternator will do what it needs to to try and charge the battery and will burn itself up in the process trying to accomplish this . To remedy this one has to check/clean all connections on the + side of the system . Negative Side : Put 1 voltmeter lead on the alternator and 1 on the - battery post and do the same process as on the + side of the circut. We all know the import electrical stuff now a days is basically junk but I find it hard to believe that there are 4 bad alternators and something is causing them to fail .