replace 4wd relay...where is it located and approx price to replace

dash display will show 2wd and when i try for 4wd it does not engage...dash display will go blank... sometimes when i drive the dash display is blank...if i restart the engine it will show 2wd. this happened when i first bought the truck new in 2005...approx. 1 month later.

What makes this problem better or worse?

restart engine and the 2wd dash display appears

How long has your 2005 Nissan Frontier had this problem?

off/on for a few weeks