Had a new battery installed today so picked up a pack of 10a fuses. Plugged one in for the NPP and no change. Looks like vacuum/solenoid next on the list.

I have LT,no cats,mufflers gutted out, and those things stay OPEN! Lol I only close them when I go into my neighborhood.

Plug a vacuum gauge into the line at the solenoid, if you have vacuum it's probably the solenoid.

Suck throught either one of the solenoid ports, and make sure that no air can pass through either ports without power to the unit.

At start up the NPP controller powers up the unit to open the port and allow avacuum to pass through it from the intake manifold to suck the gates closed.

Next start the car, or put 12v on the electrical connector and now the ports should open so you can suck air through them.

:-)

CI GS, When I 1st installed my Southern Car Parts M/W Switch the NPP was working
and the Switch was working...Within a couple of days the switch stopped working
and the 10AMP fuse repeatedly would blow in the fuse adapter (plugged into bottom
right corner)

Paul from RPI/ Southern Car Parts) sent me another M/W device and its not making the
NPP work either...

1) Why did installing the M/W switch cause my NPP System to fail

2) Do I just assume it the Solenoid

3) If I replace the solenoid will the M/W switch damage it ?? (Again)

Chuck Auburn,WA

Chuck, I have no idea whether or why the M2W switch damaged the solenoid. All I can tell you is that a few weeks after I put one on my car, the solenoid fried itself in the middle of a long drive and the exhaust flaps suddenly opened. Someone on here advised me to check the solenoid and sure enough it was melted. I removed the M2W and solenoid and ran the car without the solenoid for a bit and then ordered and installed a new solenoid and I haven’t had an issue since. I wouldn’t waste my time with the M2W. Just buy a Dashlogic and enjoy full control of the solenoid and many, many more neat features.

08 Vette npp stays open intermittent
 

Sometimes the NPP works fine and sometimes it gets stuck open. I have the mild to wild remote and again sometimes I open the exhaust and close it with the remote went fine and other times it's sticks open and won't close until I shut the car off and come back later. Does this sound more like a vacuum line or the solenoid. I have no patience to start testing lines I'm wondering if it's most likely just a solenoid . And if it is the solenoid would it work intermittently like this thank you

Just a suggestion....I added NPP mufflers after I got my C6. It was not a stock NPP setup. While I purchased the NPP in a box with the vacuum line kit, I did not yet install it. I am not in a rush to do that since I like the sound so much. Is it possible that your previous owner did what I did? If that is the case, you won't see any "issues" discussed above. I think you can check to see if you even have vacuum lines?

Good luck!
Jon