My rad switch is reading infinite ohms.

It appears my fan relay is different from yours. I've removed it and the turn signals, seat belt warning, heater fan are working without it.

On my 89 740 fuse 7 is only for the cooling fan. It is fuse 16 which controls the heater (blower) fan.

There is no current through fuse 7 with the ignition on. I don't dare measure the current at it with the engine on. I have fried an ammeter once so I don't fancy frying another one. Current meter is fused up to 2.5A. 10A socket is unfused. I'm thinking of putting in the lowest fuse in fuse 7 (15A perhaps or maybe 10A if I can find one) and see if that trips with the engine and cooling fan on. I figure a blown fuse or two is better than a cooked ammeter? If the cooling fan can run with 15 or 10A fuse then maybe I'll test it using my ammeter.

I did not replace the relay with a used one. Since the original relay was almost 19 years old, I thought I might as well replace it with a brand new one.

Thanks for help so far.