Recreational Vehicle Lpg Tank Valve/gauge problems of the 2008 Chevrolet Uplander

Drove the van home that same night,before we pulled in the drive way , the van over heated ,the brakes had a spongy feel to them after 15 mins of driving , tempturae gauge never went pass the half way make when the red indicator came on on the van totally shut down no power , I almost flip the van over. I have replace the brake twice in 3 weeks of each other. Then light on the dash came on when tempturae were cold , rainy, foggy, out side , and when it got hot tempturae out side the dash light at night time started to flicker on and off ,then about 30 seconds later the dash lights stayed off and never came back on. Also the van started to have engine not wanted to turn over, and would also loss all power to vichele leaving us stranded out in horrible weather conditions outside with are childern.