when I had mine I ran it right off the side of the vp unit with a fitting with a test port and it worked great. I am still using the fitting with my isspro gauge hooked into it now. I think you have a wiring issue with your whole box. Call them send it in and have it tested.

 

 

sent my dads in 2 times for his 3rd gen it would just stall all of a sudden. so don't feel too bad.

 

still formulating here...gonna go around today after work and see if i cant find a new fitting somewhere here in town and try that. and i guess if that doesnt work then ill have to take it out and send it in. gonna try and test the signal too.