No idea how to fix the yellow light issue. i have the same issue.  as for the pumps...  there can be many problems.  the inside of the copper plate may be gunked up. or air in the pump. does the pump spin? get a 12v power brick and only power the pump. should sound like a muffled humming. if its loud you have air.  did you try liquid pro for the paste?  I'll buy your broken rigs. Private Message ME