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Blowing 30A Fuse after VR move

Keith Williams

Well Known Member
On my last few flights my charging system would not start charging until a few minutes after starting. Then it would begin working normally.

Today I decided to move the regulator inside. I did the move but did not mark which of the two white wires went to the R terminal and which to the B terminal. I figured Vans instructions would cover that when I got to reinstalling them. Wrong. I guessed which way they went. Turned on master and the 30 amp fuse blew. I replaced the fuse, swapped the position of the two white wires, turned on the master and the fuse blew again.

With the old Skyview wiring diagram I have I cannot follow the P156 circuit that carries the two wires from the regulator to somewhere??

I have done two tests:
1. With ohmmeter from the wiring connectors to ground. No contact with the two G blades or the C blade. With both R and B initially 50 ohms building quickly to near 200 ohms and then nothing.
2. With voltmeter from battery positive to the connectors. 0 volts for the two G blades. 12.9 volts for R&B blades. 9.5 volts for the C blade.

I have evidently caused a short somewhere but I do not understand the charging circuit enough to figure out where. Can someone out there help....please....

Incidentally, in doing the move I noticed that the B wire was not fully seated. So I am hoping that was the root cause of my initial charging problems so I am not working on moving a near deathl regulator.
 
Keith, inspect the white, 12 gauge wire along its entire length, from the regulator to the fuse module. It may be grounded. If you don't see any issues, unplug the regulator and try again with a new fuse...for this test I recommend using a much smaller fuse, we are just testing the wire for a ground. If the fuse holds, the ground is in the regulator.
You can't wire the +B and R pins backwards, but you can install them in the wrong pin location, like the adjacent and vacant L pin position (that is grounded with no regulator output). The +B and R pins are jumped together in both the harness and the regulator, it's the same signal. Don't install the Faston backwards in the plug as that will interfere with correct mating.
No output is one of the typical failure modes of the regulator, moving the regulator won't fix it...the damage is done, it needs to be fixed or replaced. But let's clear your ground first.
 
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I have looked over the wire but will check more closely and great suggestion to try it without the regulator. Why didn't I think of that?

Thanks for the next steps suggestions!
 
Mike,

With the regulator disconnected and master on:

- the fuse does not blow.

- in the connector the white wires (R & B) both showing full battery voltage

I am wondering if I can check the regulator. None of the pins on regulator show continuity to the case. There is full continuity between the B and R pins. Is that normal? From your first post I got they idea that they are jumped together in the regulator so I guess that would be normal.
 
Keith,
Yes, B & R are jumped together both inside of the regulator and outside in Van's wiring harness. Like Mike wrote, it does not matter if the B & R wires are swapped. Mike will correct me if wrong, but it seems that even if the B & R wires were connected to the G terminals by mistake, the fuse would not blow.
Since you have eliminated the aircraft wiring as causing the short circuit, the regulator is most likely the cause of the blown fuses. I would replace it. Even though an ohmmeter check does not show a short circuit, the regulator can be defective after burning open a short circuit.
Buy a new regulator. Even if the existing regulator is not defective, it is good to have a spare. But chances are that your regulator is bad.
 
I see no signs of heat or other issues with or around the pins or the connector areas of the regulator.

My next step is going to be a new regulator, probably the "Deere" style I see written about.

I did find a scraped place on the white wire insulation. But it does not appear to be scraped through to the wire or wires. I will check it some more.

The white wire is barely long enough to reach to the Van's recommended location. I would like to lengthen it a few inches. Will investigate that tomorrow, as well.

Thanks again for the help, Mike and Joe.
 
Close out on VR Move

Mike and Joe, the VR move is finished. Two comments in closing:

1. You were right in your first stab at why fuses were blowing. When I got the wires all the way back out I found that the scraped part I had noticed was, indeed, all the way through to a short. Lesson - follow the Vans instructions about protecting the wires by putting some sort of shield in when pulling wires through that tight spot. (Or make another hole.)

2. I installed the JD type regulator purchased on line ($23, free shipping). The hook-up was easy with your info in previous posts. It seems to be working better than the Ducati - 14.2 volts instead of 13.8 and seems to do it at a lower engine speed than I remember with the Ducati.

Again....what a great resource this forum is. Thanks for your help.
 
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