This can be an issue if earths are not connected properly ..
Agreed , Bad earthing is the most likely cause They tell me at the workshop that in new type vehicles the radiator tanks are plastic and if not grounded will be subject to wind induced static so over time they corrode . The radiator bolts are normally not into the metal body surrounds but into plastic inserts so are insulated from earth, they over came it with an earth wire to the under body metal work.
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