above is kinda a high price somewhere around 100 maybe on ebay.
but look up mercedes k40 and then look up chry crossfire rcm. the limited and the srt6 use the same rcm.
if you know someone near you that would let you swap rcm's to check it.,but we know it is the rcm
so you could just get a new one and then as pizzaguy said,,

,and i quote "I would order a new RCM, then send your bad one to DJ in Arizona
FOr abotu $65 he will replace the relays and reflow solder. You will then have a spare to carry around with you."