Need some mechanic info. My radiator fan was not working. Bought a new relay switch, no help, checked out radiator fan switch with a paper clip, it came on . But when I reconnect the switch the fan doesn't come on. What could be the problem?

 

Check all your grounds. Had a similar issue with an EG when I was a teen. I think it was the condenser fan, would t come on, turned out to just be a loose ground wire.

 

Test drive with the switch jumped so the fan runs all the time. If the engine still overheats, there is a different problem.

Pushing paper clips etc into the connector can bend the pins so it doesn't make contact with the switch. Use soft stranded wire instead.

 

The radiator fan on a d-series barely ever gets used unless its in the dead heat of summer. You need to check temperature readings to verify when the fan should kick on

You haven't even told us if the car is over heating, it seems like you just noticed the fan didnt kick on or you havent seen it on and youre imagining a problem when there isnt one