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On 7 Oct 2003 at 12:14, Mike Wodkowski wrote: It sounds like you have already checked all the simple possibilities, except for an internal shorted wire. > One question: difference between your test and the Bentley fig 6-4 test is > that Bentley says to disconnect BOTH DF and D+. > > So I got different results from the bentley test than from yours. > When I shored DF to ground using the Bentley test, I got a big fluctuation, > up to 25 V, which Bentley says should have been more like 12v with the > engine at idle. > > When I did your test and shorted the DF to ground, I got zilch. > > Why the different readings? Perhaps this is the key. I suggest that you repeat the test to make sure that this is really what you get. The only difference between the 2 should be that there is absolutely no load on the generator with the Bentley test. In my test, the VR and battery are still connected, which will tend to "moderate" things a bit. I this is really what you see, then there must be something that is shorting the D+ wire to ground. This could either be in the middle of the wire somewhere, or at the VR. Make sure that nothing has rolled under the VR and shorted it under the back seat. You could do this as a test: Remove the wire from the D+ terminal of the generator. If there are 2 wires, remove them both. With the engine off. Measure the resistance to ground of each wire. The big D+ wire should measure about 35 Ohms to ground and any other wire connected there should measure infinity. If one of these measures close to zero, track down where it is shorted to ground. If it is the big D+ wire, disconnect it at the VR end and measure it again. If it is still shorted, there is a short somewhere in the middle of the wire; if the shoft went away measure the resistance to ground of the D+ terminal on the VR. It SHOULD measure about 35 Ohms. It really sounds like you have a short to ground somewhere that is keeping the generator from getting started; normally it has to "bootstrap" itself up in voltage until it can put out enough to keep itself going. If its output is shorted to ground it can never get that far. BTW, alternator folks should note that this won't hurt the generator, but it will destroy an alternator. If the short to ground is in one of the OTHER wires connected to that terminal, just leave that wire off. Let us know what you find. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org