hi guys i have installed twin electric fans on my jeep but i have a problem with the wiring i have them wired through a relay and thermostatic switch i cant seem to wire it through the ignition i have power wired to terminal 30 of the relay from the battery, earth to 85 ,fan motor to 87a and power through the thermostatic switch via the battery to 86 this works fine but the fans run untill cold after i stop the car sometimes for 8-9 mins as this might drain my battery i wanted to wire it to ignition source but when i run the thermostatic switch through the ignition and back to 86 the fan stays on all the time untill i turn the ignition on the it works as it should any ideas what im doing wrong i would like the fans to stop as soon as i turn off the key no matter what the temp is
cheers

 

The terminal 87a is a normally closed so that would be constant on. Try the fan on 87. Then with the ignition powered thermostatic switch, when your key goes off then that the coil will no longer be energized and the relay will go to its normally closed position which shuts off power to the fan.

 

great i just read this else where ill give it a try cheers

 

this didnt help just made the switch work backwards ie only on when cooler than a certain temp did go off with ignition though

 

Weird.

Should work as follows:

BATTERY (+) to 87
GROUND 85
FAN (+) 30
IGNITION (+) 86

So when the ignition is on and the thermo switch kicks in then the coil will energize and allow the fan to come on.

What kind of thermo switch are you running?

 

run the wires the way to have them. but, for the ground you have connected to 85 i would change it up a bit.like so...

add another relay into the mix, but use that relay to switch on and off the ground.

wiring for extra relay

87 goes to terminal 85 on your original relay
30 goes to a constant ground
85 goes to a constant ground
86 goes to an ignition on(key-on) power source

this setup will allow the fans to only work with the key on.



this can also more than likely be done using a single DPDT relay instead of the 2 standard relays....if, you'd want to take that route

 

just a standard capillary action one with the dial on top you have the battery going to 87 and 30 to the fan

 

Whats the brand so I can see how it works?

You can have 87 and 30 changed to go the other way and it wouldn't matter, once the coil is energized, that circuit is completed.

 

its not branded here is a pic of the wiring diagram it was supplied with this how i wired it but like i said the fan comes on no matter what the thermoswitch is set to with the ignition off works fine with ignision on

 

its like the thermo switch is closing the circuit when tyhere is no live feed didnt think it was possible

 

Thinking that thermo switch might be bad then. The way its shown though, if that thermoswitch is normally closed, its going to allow the fan to run, if its normally open then when it warms up, it closes and its going to allow current to flow thru the coil, energizing it and the contacts will pull away from 87a, shutting the fan off. Terminal 87a is normally closed or constant on.

 

got it sorted by adding a seperate relay to switch the battery feed to the first relay with the key cheers for your help