Check, and clean all your grounds.
unbolt, wire brush, wire wheel, scrape, all the bolted ground connections and coat them with a silicon spray or even spray paint (to keep connection clean)
under the hood and under the dash.
This could fix the problem (I've seen loose/bad ground do stuff like what you are saying), it not it will probably help something, certainly won't hurt anything.
While you are under there, you may want to leave the radio on in case you wiggle some wires that are causing the prob.
4-wheeling is about going where others can't won't or don't think it's safe.
Freedom. Exploring the wilderness, or nature, whatever... - NOT paying to go on someone's roller-coaster ride, or go-cart track!
"The price of freedom is eternal vigilance." - Thomas Jefferson