| Did you check the big white connecting block behind the battery tray/regulator?
It should have a couple of yellow wires going into it...pull the connector apart and take a look inside. Does it look OK?
How do these yellow wires look as they cross across the engine over to the other side. They can become very corroded and brittle over time due to the heavy current loading they carry, and the fact they are not upto the job! | 
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