To check the power dist pin .. remove battery leads (always neg lead first ) .. slide the battery to the o/s .. use a long screwdriver to push the red tag down on the positive lead .. it should then with a screwdriver lever out and expose the pin.
You dont have to totally remove the positive lead from the pin as it can be a bit of a pain to refit .. you need to expose enough to see if theres corrosion there ... pin is chrome plated .. if brown its no good .
If theres just a 13mm nut that end then this mod has already been done .
High resistance due to corrosion = slow turn over of the engine on starting .. extreme corrossion will cause flat battery symptoms .
If the lead wont move back and is stiff to turn .. you have problems and need to either folow my guide or get a garage involved .
For the starter cable then remove the throttle body / plenium chamber at the front .. you then have access to the starter .