Terminal - Destination

85 - Switched 12v
86 - PWM output
30 - battery(fused)
87 - Fan.

 

yup

 

OK. IDK whats going on. I never really wired up a relay.

I am using a 5 terminal relay.

Has
30
86
85
87
87a

THis is what happened. I wired it up as posted in the first post. I set the haltech to thermofan. I set the temp to a low setting just to see if things are correct. The temp passed the set temp and the fan never came on. SO i thought maybe its the 87a terminal. With the fan attached to 87a terminal the fan still doesnt come on but it does come on when the car is shut off..... ??

 

are the 85 and 86 backwards
?

 

See if this works...my stab but I'm on 3 hours sleep...

Thermoswitch should have a ground, power, power output line

Relay
85 Switched 12v (this should be to your fan thermoswitch (power output line)

86 is Ground
30 is fused Battery +

87 is to positive wire of the Fan

Thermoswitch hits temp and completes circuit sending 12v+ switched to terminal 85 of relay. So you switch power on to terminal 85 which completes ciruit with 86 ground. This charges the coil and causes the switch in 30 fused batt + to complete circuit with the fan (power runs through positive wire of 87 to the fan with the fan ground completing the circuit).

Fan turns on...cools you down..temps drop and then it opens the thermoswitch, cuts off 12V+ to 85, coil is no longer charged, switch goes back from 87 to 87a cutting off power circuit to the fan and the fan turns off.

 

fan connected to terminal 87a comes on when car is off because it is completing direct circuit of 30 fused Battery to 87a to fan ground.

30 and 87a have connectivity no matter what is going on with the coil. So with the car off, you have direct power going to the fan via 30 to 87a to fan to fan ground.

I don't think you'll need 87a and you can get by with a 4 position relay based on what you posted.

 

Or that can be done:

Thermoswitch output to fan ground.

Positive wire of fan to 87

30 is fused Battery +

85 Switched 12v

86 is Ground

...maybe I should stop before I F this all up lol

 

I see most wired like post #5 above....but depends how you hook up your thermoswitch

 

85 and 86 are the coil. Switched 12V to one side and the trigger from the ECU to the other. Doesn't matter which.

Fused 12V supply from the battery to pin 30.

Output to your fan on pin 87.

The middle pin, 87A, can either be normally open or normally closed depending on what type of relay it is. For use with a fan just leave it unconnected.

 

Guys The original post is the correct way. I bought a new relay and wired it up the same and it worked. The relay must have been bad.



arghx and C. Ludwig are correct.

 

I believe a Haltech grounds the circuit. Im not sure if that iss how a thermoswitch works.

 

I just noticed that.

 

If the haltech grounds the circuit then you were golden to begin with as you have stated. I was going by manual thermoswitch not controlled by ECU...sorry

C.Ludwig said what I did...albeit more succinctly lol

 

I have mine wired up to the same schematics as post one. However my fan doesn't kick on. It's a Taurus e fan, and works fine when hooked up to the battery. I tried lowering the temp in the Haltech and at just doesn't come one. It's hooked to the same relay the same way. As well as a fused lead to the battery. Any thoughts?

 

Figured I would bring this thread back rather than start a new one as it has good info.

I currently have everything hooked up like the above posts minus my switched 12v. With the haltech do you still need to run switched 12v to a thermoswitch? I was under the impression that the haltech took the reading off the gm coolant temp sensor and then could kick it on at the desired temp.
I apologize for the stupid question, but I just want to make sure as my vehicle does not have a thermo switch installed.

 

Yes, you need the switched 12v on #85 or #86 on the relay. Follow exactly what others have posted:


85 - Switched 12v
86 - PWM output
30 - battery
87 - Fan

 

Alrighty. Looks like I will be swapping thermostat housings with a friend and doing that.
Thanks for the response

 

Y'all are talking past each other. Switched 12V is "12V when key on," no additional thermoswitch needed. The Haltech most definitely uses the coolant temp sensor - it is the "thermoswitch" in this case.

 

Lol. I had feeling we werent getting across to each other.
So it doesn't require the fan thermoswitch that mounts in the thermostat neck housing? I will be installing the haltech coolant sensor in the factory location behind the housing. My current efan is wired to switched 12v accessory off the green plug. So my understanding was all I would need to do is wire up the pwm output to the relay and set the temp within the program.

Correct?

 

Correct.