Got some problems with my line lock

[Erlend / bug66]

Tried my line lock today, and it locked up all 4 wheel, and did not want to let go 

Single MC, one blended port, one to the rear wheels and o e to the line lock. I've blended one port one the line lock, and routed the two other to the front wheels. I've also done the electrical by the book, lights go one and off by the switch, and I can hear the line lock engage and "release" but the preassure remains..

Got any tips?