Dam Fan Module!! Delete?

Nathan Wallace

New Member
So I know my fan module is faulty (Rad fan runs with KOEO (key on engine off), AC fan never runs even with AC on), and the fan runs for 10 seconds after you turn the car off and walk away.
And I watched a youtube video (linked at the bottom).
Confirmed fan module failure for me.

As a result the car starts to over heat on a 25 degree + day, in slow moving or stand still traffic.
It is fine when driving though, 60kph + and comes back down pretty easy.

Really don't want to shell out $240-$330 (depending on the dealer) for a new genuine one, when it may fail like all the others in time.
And getting a second handy are rare as hens teeth, because everyone grabs them the second they hit the parts yard.
Kind of after a simpler, DIY, better fix.
I was thinking of wiring both fans to come on when the engine starts, and flat out, all the time.
Would just need to source a 12v wire that was active only when the engine was on, and use it to switch a relay, and remove the fan control module all together
Any reason why this is a dumb idea?

I could technically make my own fan control module with the AC 12v input for the AC fan, an arduino, temp sensor (to measure rad temp, just have to work out where to put it) and a couple of relays, but not sure that is necessary.

Maybe wiring it 100% is easier.
Higher duty cycle may cause early fan failure?

I know the older lancers just had 2 relays running everything. I discovered that when I went looking for 2nd hand fan modules.

Anyone done this, or something similar?
Maybe there is a better solution.



Active Member
Lifetime Premium Member
Its the most common point of failure, god knows why. Mine comes on with ignition and is sparodic all throughout my driving, often stays on until key is removed from the car. I replaced it with a spare module which was actually worse, it cut out and caused me to overheat in traffic.

Hardwire/diy option is your cheapest bet. I think theres a shop in the usa that does reco units for $100 aud but I dont know anyone here who bought one.

The basic function of the orginal module is to come on at around 60-80degrees at 25% and ramp up to 50% then 75% and finally 100% by 100 degrees. Keep the fan on for a short while after the engine is off and turn he ac fan on when the ac is switched on.

Personally I’d wire up a pair of switches, 50% and a 100%. Just turn the 50% on once the car is warm, then 100% if temps are high or youre sitting in traffic. Hav the A/C fan run 100% as you have the a/c on. Be sure to wire them to an igntion switched power sorce, or you will kill your battery if you forget.

Let us know how you go!


Active Member
Lifetime Premium Member
Other option you could try is buy one of those digital temp monitors (currently on eBay $109) that sound alarm/ Or light that comes on when temp gets to a preset temp level that you can set yourself, one model I saw came with a accessory output terminal to run trigger for relay to activate your fans, even saw one on US eBay site that you can set two temp trigger points.
As for air con you could possibly run trigger wire from aircon power on to extra fan power on via relay, that should go a long way to sorting out some or most of the problems.