Northern New York rust preventing TCM and lights to stop working..Bcause of splash shields rust, i had to run a wire from the negative side of the battery to a wire junction box . I cut all the factory minus wires to signal, headlights, side markers, etc and spliced them together and they now all operate..The TCM P0700 code was eliminated by cleaning the aluminum off the module and running a separate wire from the minus battery terminal junction box i built and attached it directly to the mount bolt of the module itself, not the mount bracket..Maybe this information can help others with similar rust issues. And, the automatic transmission operates as intended..
