xjr10

Im wiring up my electric fan to a toglle using a relay. Im not much of an electrician so i have a question. My fan turns on when my toggle switch is off and turns off when i turn the toggle on. Is that correct? This is what i used to wire the relay up.

SoCalxJ4.0

Check this out. Works great.

https://www.cherokeeforum.com/f51/ho...lec-fan-48541/

DortDizzle

There are a bunch of different ways to do this, and there are many on the forum. Might need some more info?

What year is your XJ? The fan operation is a little different in 97+ years.

Do you care if the check engine lights is tripped?

There is a relay that controls the fan between the ECU in your diagram.

For safety it would be good to put a 1amp fuse on your bridge wire. That way if your relay fails as a short you don't catch your Jeep on fire.

It looks like your method might not trigger the CEL because you are just providing a new power path for the fan. The ECU monitors the current on the pin for the fan relay. If it doesn't get the right numbers it throws a code assuming the relay is toast (+97 only I think).

94XjSport94

My sig

xjr10

Its a 00. No i dont want the cel on.


Im on the app. Cant see it.

94XjSport94

Heres the link:
https://www.cherokeeforum.com/f51/el...switch-132465/

Dan91

This writeup here is the one guaranteed way not to get a check engine light on 97+ all other ways seem to be hit or miss.

http://www.naxja.org/forum/showthread.php?t=1025399

xjr10

I already have everything wired up the way the diagram i posted is. I just dont understand why the wire from my toggle to the 86 pin on the relay must have power to STOP the fan from running. Wouldnt that drain the battery over time? I dont drive it much so it sits a lot.

Jay420

The fan turns on when a ground is added. Thats why it comes on in your "off" position. The fan has constant power.

I just tapped into the blue/pink wire straight to the toggle. And toggle to ground. Flipping toggle activates ground and turns on fan. No cel and fan will still operate as normal if the toggle isnt on.

94XjSport94

Yup... thats my write up in one sentence basically

jcwclm

This shows to ground the 85 pin.

http://www.mp3car.com/the-faq-empori...ire-it-up.html

DortDizzle

The polarity on pins 86 and 85 (relay coil) is only important if there is a transient suppression diode built into the relay. They stop high voltage spikes when the relay is turned off.

tobtech

I just used a toggle switch to ground the blue/pink wire to kick on the factory relay. Works but check engine light comes on. My next plan of action was to trigger a second relay that will interrupt the blue/pink sending ground only to the factory relay and isolating the side that goes to the PCM. Anyone have experience with this? I am guessing that the PCM won't be happy with that wire open either and the check engine will still come on.

DortDizzle

Yep pcm monitors current (or voltage drop) through the relay coils. Just like the mod above use the factory relay to trigger another relay that runs the fan. Use a switch to select the power from the oem relay or a constant source to run that relay. That way the new system is transparent to the pcm.

I have a schematic for how I did mine, but it is essentially the same as above. Will post later.

jcwclm

Ok i see now. Its grounded from the toggle.