I have an 2003 Lq4 / 260z car project with a reworked stock harness that retains the high & low speed fan control wires (ground sources?)from the ECM. My summit electric fan came with a relay that has large wire hookups & two small 16 gauge wires that activate the fan. One needs 12 volts fused & the other goes to a thermistat, which is a ground source. I would like the ECM to activate the fans but also have the ability to override with a switch. Can I run a switch supplying ground in parallel to the thermistat wire which I assume hooks up to the high or low speed ECM wires or would that damage the computor? Also if the Ecm is getting the engine temp information from the sensor in drivers side head, can I change it to achieve a 180 degree activation temp? Appreciate knowledgeable help.

 

You don't need any type of thermostat to control the fans. Let the pcm do it. The temps can be reset for the turn on and off when the pcm is tuned. Use the common 12v Bosch type relay and let the pcm ground the relay to make the fans come on.

 

I have HP tuners. Just not very Knowledgeable. In what area of the tuner would I find the cooling system adjustments. I can't find it. Thanks

 

I did manage to find the ele fan tables in "systems". which leads to other questions. I have a single ele fan. The options in HP tuners are. fan type 2fans/auxfans/or nofans? under these options is. fan stage 1 w/on&off temps fan stage 2 w/on&off temps....... Which wire from the ECM do I use, They are Identified as low speed or high fan? Thanks.