As many of you may know or have found out there are some compromises when you switch over to an aftermarket EMS. One major one for me was the fact that for the life of me i couldn't get the fans to turn on with a/c on unless i was above the coolant temp threshold. some old thread

https://www.s2ki.com/s2000/topic/895...ch-is-pressed/

This is after countless hours of sending logs to AEM and checking my tune and going over all my fan relays and electrical system It turns out the AEM software just wont do it. Apparently its not an issue just known to the AEM v2 for just the s2000's a simple google search will confirm that its seems like mustang guys are in the same boat.

http://forums.corral.net/forums/aem-...over-ride.html


For some that's not an issue but i live in south Florida where im seeing 100+ degree days with 99% humidity. I would be in a pool of sweat long before the coolant comes up to operating temp.

looking at this schematic



Its an easy fix using a relay

i used a DEI mini relay

http://www.ebay.com/sch/i.html?_from...RECTED+BANDNEW

I wanted to keep the relay inside the fuse box to avoid even more wires and clutter in the engine bay. Plus all the wires are already there so it makes things easy. I took about 20 minutes and came out pretty good. Everything fit nicely underneath the fuse box connector cover. All wirs found on the plug all the way to the right of the fuse box they are thin wires.





Relay wiring diagram

30 Chassis ground
87a No connection
87 Green wire (ems/ecu/fanswitch wire)
86 black yellow (ignition)
85 red (a/c signal wire from ems/ecu)

What this will do is turn on the fans every time the a/c clutch is engaged regardless of coolant temp. Might also work for you guys that don't have a/c to manually control the fans using the a/c switch.


I hope this helps someone!

 

Another solution would have been to jump a wire from one of the other low side driver outputs to the fan relay output wire. Then tell the AEM to switch on that output when it sees the ac switch input "switch 6"

 

it can be done using the software outputs configuration, we did that way, we started the car, let it warm a bit and then turned on AC, the ac gas pressure went up really high really fast and then ac fan didnt come on, so we took the LS ouput and configurate via the AC request Input

So the main fan turns on the proper low side driver and configurated by temp and the ac will do it as well when the AC clutch engages.

I will take a pic from the series 2 configuration and let you know it wasnt that hard enough

cheers

D

 

Any chance of a picture of the setting?

 

I got it working on older AEM that had same issue.

https://www.s2ki.com/s2000/topic/115...#entry24023251

 

old thread i know. how would one with the a/c system removed be able to control a fan plugged into the a/c condenser fan wiring?