Electric fan relay wiring? urgent please help

[Ewing]

The relay on my electric fans was a 40amp 5 terminal, but it blew and the only replacement the parts store had was a 4 terminal.

My question pertains to which wire goes on what terminal? I have a ground, red wire that went to the radio, battery wire, and fan power wire. The relay has terminals 87, 85, 86, and 30. Which goes where?

Any help would be appreciated> I have read many many threads on here as well as other sites and none of them give clear instructions on what wire goes to each terminal. I don't want to start a fire.

[cotbu]

-30 = constant [positive (+)] power (usually wired directly to car battery)
-85 = coil ground (wired to the negative (-) battery terminal or any grounded metal panel in the car)
-86 = coil power (wired to the control source. could be a switch, or it could be the car's IGN or ACC circuit.)
-87 = switched [positive (+)] power output. (when the relay coil is powered, lead/pin 87 is connected to lead/pin 30)

30= battery constant power 12v and should have a fuse.
87= your fans power and whatever config you have it set to(high/low speed)
86= ignition on power 12v trigger in this config
85= ground

I'm assuming this is not controlled by a thermostat.

[KiLLeR2001]

cotbu is correct. generally, i switch the roles of the 87 and 30 but it does not matter. the 5 terminal relay has an extra lead called 87a. This is only a source of power when the relay is not activated. For the purpose of electric fans it is not needed.

[Ewing]

-30 = constant [positive (+)] power (usually wired directly to car battery)
-85 = coil ground (wired to the negative (-) battery terminal or any grounded metal panel in the car)
-86 = coil power (wired to the control source. could be a switch, or it could be the car's IGN or ACC circuit.)
-87 = switched [positive (+)] power output. (when the relay coil is powered, lead/pin 87 is connected to lead/pin 30)

30= battery constant power 12v and should have a fuse.
87= your fans power and whatever config you have it set to(high/low speed)
86= ignition on power 12v trigger in this config
85= ground

I'm assuming this is not controlled by a thermostat.

You sir, are a gentlemen and a scholar. Thank you :bowdown:

[Ewing]

cotbu is correct. generally, i switch the roles of the 87 and 30 but it does not matter. the 5 terminal relay has an extra lead called 87a. This is only a source of power when the relay is not activated. For the purpose of electric fans it is not needed.

Good info thanks. I was wondering what the 87a was for.

[army240]

Good info thanks. I was wondering what the 87a was for.

There is contact between 30 and 87a when 86 doesn't have power or 85 doesn't have ground.

You could use it to put a red LED to tell you that your fan is off, and a green LED would be connected in parallel with your fan so it comes on with your fan... but this is just an example!

:wan:

Frank

[Ewing]

There is contact between 30 and 87a when 86 doesn't have power or 85 doesn't have ground.

You could use it to put a red LED to tell you that your fan is off, and a green LED would be connected in parallel with your fan so it comes on with your fan... but this is just an example!

:wan:

Frank

That's actually a pretty cool idea. I think I may switch to a thermostat setup down the road so I may use this.

[shalezzz]

-30 = constant [positive (+)] power (usually wired directly to car battery)
-85 = coil ground (wired to the negative (-) battery terminal or any grounded metal panel in the car)
-86 = coil power (wired to the control source. could be a switch, or it could be the car's IGN or ACC circuit.)
-87 = switched [positive (+)] power output. (when the relay coil is powered, lead/pin 87 is connected to lead/pin 30)

30= battery constant power 12v and should have a fuse.
87= your fans power and whatever config you have it set to(high/low speed)
86= ignition on power 12v trigger in this config
85= ground

I'm assuming this is not controlled by a thermostat.

if it were thermostat controlled
i would use 10g wire and

85- would be 12v constant with fuse 30a
86-would be thermostat positive (the negative of the thermostat will go back to ground or neg side of battery)
87- would be fan positive(negitive side of fan will go to bat neg or ground)
30-is where im confused. do you split that 12v line after the fuse and have 1 go to 85 and 1 go to 30???
my goal is to have it stay on until the thermostat reaches below 170 even when the cars off to allow for proper cool down
any help would be awesome this is what im going off of.
http://www.aaroncake.net/RX-7/efaninstall1.gif

[KiLLeR2001]

if it were thermostat controlled
i would use 10g wire and

85- would be 12v constant with fuse 30a
86-would be thermostat positive (the negative of the thermostat will go back to ground or neg side of battery)
87- would be fan positive(negitive side of fan will go to bat neg or ground)
30-is where im confused. do you split that 12v line after the fuse and have 1 go to 85 and 1 go to 30???
my goal is to have it stay on until the thermostat reaches below 170 even when the cars off to allow for proper cool down
any help would be awesome this is what im going off of.
[IMG]


Put down the wire cutters, step away from anything electrical before you kill yourself.

[shalezzz]

Put down the wire cutters, step away from anything electrical before you kill yourself.

Any way.... How is that schematic different than what i described? I'm not trying to kill my self ya know