Have you tried disconnecting the parking brake? It connects to ground to turn on the brake light. If that does not take care of the problem you need to look for a ground short somewhere. If it does take care of the problem then you need to see what in the parking brake is causing a short. This sort of thing can be a major PITA to fix.
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KDP tab fix info and fuel system article
jgeorge1@suddenlink.net '95 2500 CC auto 4X4, 3.54, EGT, boost, fuel pressure, trans temp guages, PacBrake, TST #5, DTT VB, DTT triple disk TC, DTT billet flex plate, Cummins chrome kit.