When cranking that side should have 12v back fed from wire that runs starter to coil-------You aren't getting proper volts -and you said your volt was 11.95 ??????? most batteries/charging systems will be nearer to 13-14 without any draw on them-------I think you have some serious resistant problems in battery cables/ posts/ clamps-----Its common that with age that the copper corrodes from the acidity around the battery end and also road trash stuff(road salt) underneath by the starter