Cascadia speedometer not working, engine brake and cruise control not working as wel

[3406E]

I have similar problem with my 05 cm870. Gauge only works when truck goes above 25mph and my jakes cut out by itself and only stays on when there is good amount of compression in the engine; when it the truck slows down the jakes get weaker like it skips from stage 3 to 1 by itself. Also like 1 day out of each week the cruise control chips out by itself weirdly sometimes when I run over a bump. Funnily all these problems all occurred in a day all together about 2 weeks ago. I have not found out the issue.