Have Volkswagen Questions? Ask an Expert Now.
on the output side of the alternator, the post of the alternator that has the wire the runs from it to the fuse box above the battery. Goes to fuse 177 if I am not mistaken.
I have 0.1 ohms of resistance from the wire/lead that connects to the back of the alternator to the fuse box. I have 0.1 ohms of resistance on the fuse itself and the wire that connects from the fuse to the positive battery post terminal. I even went as far as testing resistance from the positive batter post terminal to the end of the lead that connects to the alternator and have 0.1 ohms resistance in that also. There are two wires that plug into the alternator in a standard clip connector. I take it that one has power at all times and that there is some type of relay or resistor that lets voltage go through to illuminate the cluster signal when the alternator is not performing as it should. Is that correct?
Ohms tests do not tell you anything. You can have one strand of wire and have good connection, but under load it will have a very high voltage drop. To properly test circuits, they are done under load and a voltage drop test is performed. Simple way to do this is start the car, with the running and the DVOM, put on volts DC. Place the positive lead to the back of the alternator, then place the negative lead on the Positive battery cable. Anything more than 0.10 volts you have a problem.
FYI, ohms are used to test sensors, and items like that, volt drop tests are done on large circuits
Makes sense, I remember that from my automotive degree plan I am currently taking. Brain fart on my end. However in a slim defense, I didn't have the alternator in the vehicle to perform the procedure you mentioned, so I utilized the ohms test. I work on diesel equipment in the military and I am used to there being a activation wire for a voltage regulator. I am a novice to say the least on the civilian side so not seeing a activation wire threw me off, because I was wondering what activates the alternator regulator and controls the voltage that the alternator produces. I undertand that this isn't automotive electrical 101, lol, but if you wouldn't mind I would like to know.
Thanks for your patience and help!! Have a good evening!!
Just got done putting everything back together and the alternator is putting out 14.24 vdc. Did the load test as your described earlier and got .004 as a readout. Don't know what the issue was, but it is fixed for right now. Once again, thanks for you help!!