How to: Hot-wire fans to always be on low with key on. Great for drag-strip

[acammer]

Hey all, I thought I'd share a quick tip for easily "hot-wiring" your fans to run constantly on low when ever the key is in the on position. This is great for trips to the drag-strip where you want to carefully manage your coolant temps. Stock thermostats will benefit from this, and a 160*F T-stat will be even more impacted. My friends ZL1 used to heatsoak terribly waiting to get up to the line, this modification greatly helped his consistency at the track.

I guess I should share the obvious disclaimer here - if you're not comfortable with any of this, by all means don't do it. The last thing I want is somebody ruining their PCM or starting a fire by doing something foolish. I've installed this modification on my own car, as well as a friends, as well as disassembled my fuse box to install a permanent fan switch for both the low and high speed circuits. I take my time, and double check everything. I suggest you do the same. I accept no responsibility for you or your actions.

What you're doing here is grounding the signal side of the relay that controls the low speed fans. I've done with with my 2011 SS, as well as my buddies 2015 ZL1. My SS now has a permanent fan switch inside the cabin - it uses the exact same method with some cleaner wiring. On the ZL1 this does throw a code for something about fan control - apparently it has some sort of fan circuit feedback system than the SS does not. The car still functions fine, but just be aware of that potential if you attempt this.

All you need for this is about 18" of wire, a ring terminal, and a 10mm socket and driver. Just about any light gauge will work as this is very low current, something light like 20 gauge will be much easier to install with the relay. Attach the end with the ring terminal under the bolt that retains the upper radiator mount on the passengers side of the car. Remove the bolt, and reinstall with the ring terminal under the bolt against the radiator support. This will be your ground.

The other end of the wire needs to be stripped back about a quarter of an inch so it can be tucked in with the switch signal ground terminal on the low speed fan relay. The relay is K613 in both 5th gen Camaro's I've done this with, validate that is the case for you with the reference information in the fuse box under the hood on the passengers side of the car. Remove the relay, and pay attention to the orientation to be sure you reinstall it correctly.

You're looking to ground the switch signal ground terminal on the relay. This is the terminal closest to the drivers side front of the car. Re-install the relay with your wire alongside that terminal. It will require a little extra effort - if it feels like its too tight (it will feel very snug) then you may need to thin out your wire. The relay will not seat perfectly, but it should be pretty close.
Route the wire out the front of the fuse box, and ensure it is out of the way of any fans, belts, etc.

Now, when you turn the key on (engine off or running) both fans will run at low speed constantly. This is great at the drag strip, you can keep the fans running to keep things cool while waiting to make your pass, and you can even run them with the engine off after making a pass to help circulate air throughout the engine compartment and cool things down. When you're finished, simply remove the relay and wire, and reinstall the relay. You can leave the wire grounded for next time, or remove as you see fit.

If you're like me, you may want to take your test light and validate each pin in the fuse box. On both cars I've checked (and it should be the same for all) the pin closest to the passengers front of the car is constant power, the pin closest to the passengers rear of the car is key on power, the pin closest to the driver rear of the car is the power feed side of the fans, and the pin closest to the driver front of the car is switchable ground controlled inside the PCM to trigger the relay.

I've seen this mod accomplished by bridging the constant hot straight to the power feed of the fans, however I prefer to keep the relay intact and let it do the switching of the high current stuff, rather than getting arcing when you plug that bridge in.

Keeping coolant temperature and intake air temperature under control is key for consistent drag-strip performance. Too much of either and the PCM definitely starts pulling timing, and that results in sub-par performance. I hope this helps you guys.

[christianchevell]

I seem to recall a company making a chiller the RX company a a/c operating one that makes the IAT lower for boost but would be good for some people out there who may not know about it also........... http://www.rxspeedworks.com/wp-conte...perchiller.pdf

https://www.rxspeedworks.com/ then there is the ice-olator thing??? and of course other stuff, but I don't see anyone using the super chiller out there....??

http://www.superchevy.com/how-to/eng...ooler-install/ and wonder if they make them anymore...?

[jrhagen]

Great FYI but who can find a 10mm socket?

[acammer]

Originally Posted by jrhagen

Great FYI but who can find a 10mm socket?

[OneBadvATE]

Excellent write-up! I just snapped a couple of pictures highlighting the radiator bolt grounding location as well as a picture highlighting the location of the relay in the fuse box. This proved to be a big help in keeping the car around 180° on average in the staging lane while keeping the fans running while the car is off. Very quick and easy to do and was well worth it since I was able to finally run an 11 second pass

[acammer]

Good call on the photos, thanks!