2009 Frontier keeps blowing VBC?

[tumbler510]

Hi All, I have a 2009 Nissan Frontier and here is my problem timeline:
* NOTE: My truck does not have the exact temperature dials, only the blue/red knobs.

- Driving on hot day, fans go 100% on. Can not turn off, or turn down. As soon as the ignition is turned on, the fans are 100%
- Disconnect VBC, fans stop
- Order replacement VBC (http://www.rockauto.com/en/moreinfo.php ... 2675&jsn=9). Plug in in driveway, fixes issue. I can change the fan speed from the center console.
- Next morning pull truck out of driveway, and retest fan controls. They are 100% on again.
- Go through Nissan Frontier Heating and Air COnditioning (HAC) troubleshooting, and get everything reading OK.
- Grab a VBC from a Nissan Quest @ Pick-N-Pull, plug in, fans are at 100% and the VBC gets super hot
- Order ANOTHER VBC (http://www.rockauto.com/en/moreinfo.php ... 1462&jsn=8) and install. Almost immediately fans go to 100% and the VBC begins smoking/blistering.
- Try a replacement fan. Still 100%
- Troubleshoot with Electrical Engineer friend to verify I am not insane. We create a basic wiring harness and attach directly to the battery. VBC turns fan onto 100% so we are fairly certain the VBC is to blame.

But the issues now is WHY is my truck killing the VBCs? We used a 15A fuse with our home-brew wiring harness and it didn't blow. I have no blown fuses in my truck either.

Any help would be greatly appreciated!

[tumbler510]

UPDATE:

I got a new unit from Beck/Arnley from Rockauto and tested it with a multimeter vs the blown and OEM units.

There are 2 connections that showed differences in resistance from the new to the old.

I plugged the new one into the truck, and turned the accessory on, VBC works like a champ for a few minutes. I turned the ignition on, and again the VBC keeps working perfectly. Then i turned the ignition off, and turned it back on, and the VBC was blown.

So something happened when turning off the ignition that caused the VBC to fail.

Any ideas?