I ordered a two spade terminal radiator fan temp switch from rockauto. They sent me a single pin switch. I'm running an after-market fan and spdt relay. I understand how the two node switch works. How does the single pin switch work (how does it ground)? Is there a way I can use this one instead of the two spade one?

 

Rock auto already issued me a credit for the shipped temp switch and let me keep it.

 

1987 GL.

single pin temp switch will ground thru the switch itself....some sub's (like my brumby) have a single pin switch

make a ground strap from the radiator to the body, and the swithc will ground. you got one from an ea81 model which is designed this way.

Thanks guys. I was thinking of grounding the radiator if I used it. This way I'll save a little dough. Is the temp rating similar for the EA81 vs. EA82 style switch?

single pin temp switch will ground thru the switch itself....some sub's (like my brumby) have a single pin switch

Not quite. Yes it grounds through the body of the radiator, but you MUST have a ground strap from the radiator body to the frame of the car. Without that, the single pin switch won't do you any good since the radiator body isn't always properly grounded.

The simple ground strap will only work if you have metal tanks on your radiator that the switch screwed into. If plastic tanks then you would need to ground the switch body to the chassis. (The use of plastic radiator tanks on the EA82 was a major reason to go to a separate ground for the switch itself.)

The simple ground strap will only work if you have metal tanks on your radiator that the switch screwed into. If plastic tanks then you would need to ground the switch body to the chassis. (The use of plastic radiator tanks on the EA82 was a major reason to go to a separate ground for the switch itself.)

 

This does have plastic tanks. I figured I'd make a small sheet metal bracket that slips onto the switch like a washer but has a tab protruding to connect a spade terminal to. Since I'm running a relay through this instead of the entire current of the fan, it should be fine.

 

On another note, do you guys put a resistor in-line with the relay? I've heard an argument both ways...