I dont have photos but i bought a boost gauge off ebay and when i got it instead of 0 it was reading 2#,,,I ended up cutting the gauge all the way around on the white round part with a die grinder, I got it on zero and epoxied it back together...it worked out good,,but i would try what Markus suggested with the heater first
I have opened up several and put them back together with no trouble. I used a very small flat head screwdriver from the backside where the ring is crimped against the plastic housing. Got it started under the ring and SLOWLY worked aroung the guafe many times and at one point even got a little larger screwdriver and worked it around untill the ring is opened up ehough to get it apart. Then used the but of the screwdriver to roll the edge back down. It wont look as good at origional but i left that since it was on the back i did not care. The key is to go slow. For your moisture i would try the heater first though.