I just got a new power supply for my bench testing of my products. This new supply is an adjustable 0 to 15 volt 0 to 60 amp. supply capable of constant voltage or constant current. So to test the new supply I connected one of my fan relays and made up power and load cables using six 16 AWG wires on each branch. I ran 60 amps for 5 minuets just to verify the supply was working and test what could fail.

Well my relay has no problems with 60 amps of current but the relay pins and their connector sockets are what produce the most heat. By the end of that 5 minuet run the pins were getting hot, the relay was just getting warm and the wires were getting warm. So now I know why the 70 amp AUX relays use larger pins on the load connections.

I use my electronic relays replacing the AUX relays but use the standard size pins (I've added sockets to my harness). But I tested the AUX circuit currents and they are well below 30 amps each.

My test socket pins are very heavy gauge metal (made for 8 AWG wire). You could never put those pins into a socket because it takes so much force just to push one pin on or off.

This is just an FYI as to why some people get melting fan fail sockets.