Hello fellow owners of Vanagons,

I have been struggling with diagnostics on the battery = isolator made by Sure Power Industries for my 86 Vanagon. I purchased a rebuilt = Bosch alternator, complete with the integrated Regulator, after both the red = charging and OXS lights for the unit came on, and after checking the output for = the alternator at the battery and alternator. Joel Walker gave me a great = number of very helpful ideas to diagnose the problems, but does not have direct = experience with isolators in Vanagons. So here I am back at the list. The Sure = Industries Model 702-4 has been on the van since its original purchase and as far = as I can tell, worked great. I recently noticed intermittent and simultaneous = flickering of the charging light and OXS lights, and they finally went out. I have = tried to reset the OXS reset button, but it does not appear to have been tripped = in the first place.  Both primary and the accessory batteries are quite = new, and hold a charge well.

Here are the things I have checked:

1. On the original alternator I replaced the voltage = regulator with a brand provided at NAPA (it fits the hole locations on the = alternator, and seems to have the same brush configuration), and made the specific = modifications to the regulator noted in the wiring diagram for the Isolator = (specifically for the Vanagon). These modifications involve soldering a length of #14 wire = to the regulator connector prong, and connecting the end of the wire to the "R" = terminal on the isolator. There are 4 terminals on the isolator, battery = 1, battery 2, "R" regulator, and "A" (the alternator). Then you cut all the = wires going to the alternator plug, and taping the alternator end of the blue = wire so that it cannot make contact. You then extend the other cut end of the of = the blue wire with a new length of #14 wire and connect to the R terminal. 2 = wires are now connected to the R terminal of the isolator. Before installing = the modified regulator, one has to bend the prong in the alternator so the = modified regulator does not make contact. I also did this. I sent a couple of = photos to Joel to show him how it was set up. In any case, the new arrangement = didn't work, as both lights remained on. All testing of the charge at the = battery or alternator remained the same as the background battery = voltage.

2. I then installed the new alternator, with the = modified regulator arrangement, and it also did not work, as no voltage change = registered over the battery voltage at the alternator or at the battery, and both = red lights remained on.

3. I then tried to test the new alternator by entirely = bypassing the 2nd battery. This is where my lack of understanding of electrical = circuits has me confused. I replaced the original (new unmodified) Bosch = regulator back into the alternator, after bending the prong back so the internal = contact is restored. I removed the contact for #1 battery on the isolator and put = it on the alternator terminal that goes to battery #1.

I then reconnected the battery and, turned on the = engine, and looked at the voltage meter. The meter seemed to stay at about 12.5 = volts, I had hoped to see it jump up to about 13.5 or more. After turning the car = off, the meter again seemed to be giving the same reading of 12.5 volts. Yet both = lights, during this test with the running engine remained off.

So here are my questions:

1. Why didn't the voltage indicate that the alternator = was coming on?

2. Here is another question: The D+ terminal on the = bosh alternator does not have any wire connected to it yet. Am I supposed to reconnect the wire that comes from the dash that was formerly connected = to the isolator at terminal "R"?

3. Is there some way that I can test the isolator to = see if it is working properly, independently without the alternator? I am told = that these isolators are very simple and almost never fail.

4. Joel thinks that it is possible that I have a = grounding problem somewhere. Where should I check if all of the above does not = solve the problems? Again, he really went out of his way to baby sit me on = this.  I can't thank him enough.

Jeff Hartman Juneau, AK

86 Vanagon