Hey Rufrob - In sorting out your wiring you've made another great step in reviving your 928...... Watch the fingers though - the consequences can be dire. In Texas you can always spot a Rodeo Team Roper because they are often missing a digit or two from dallying up. We don't want to have to change your Avatar.
Sadly - on occasion there are issues with Ebay parts. Their customer service people are usually very supportive in correcting or replacing a defective item. It may now become a matter of justifying the return shipping cost or repairing the radiator locally.
Good Luck, Michael