S.Violette Posted April 3, 2022 Report Share Posted April 3, 2022 1995 BMW M3 with G4X plug in ECU. I want to control Aux Fan with ECU and want to triple check with you before wiring up setup. The car supplies 12 volts to a temperature switch in radiator. When temperature is reached, the switch grounds out circuit and relay supplies power to fan. The BMW temperature switches alway fail leading to overheating and their settings are set from factory. I want ECU to control fan using control scheme in LINK ECU program and be able to adjust temperature startup. I have expansion loom. Key Question- Can I wire the 12V control voltage to DI7 and have the ECU “ground” out the circuit, close relay, and control the fan? I have a 1 speed fan so either red circle in diagram will work. I just don’t want to feed 12V in ECU and blow something up. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 3, 2022 Report Share Posted April 3, 2022 DI is Digital Input. You need an output to control the fan relay, not an input. What ECU do you have, an E36 plug-in? Quote Link to comment Share on other sites More sharing options...
S.Violette Posted April 3, 2022 Author Report Share Posted April 3, 2022 E36 plug-in ECU. What is your suggestion? Does G4X plug in have a digital output/switch available? Help me understand the Digital input on expansion loom. Is it looking for a 5V or 12V signal? Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 3, 2022 Report Share Posted April 3, 2022 3 hours ago, S.Violette said: Does G4X plug in have a digital output/switch available? You could use Aux 7/pin 11 which is only for auto trans models. Or Ign 8/Pin 36 which was originally evap purge. 3 hours ago, S.Violette said: Help me understand the Digital input on expansion loom. Is it looking for a 5V or 12V signal? DI's can be used for on/off type inputs such as a launch control switch or hi/low boost switch, or for frequency signals such as a speed sensor or ethanol sensor. It can be switched to ground, or 5V or 12V. You just need to set it up appropriately. Quote Link to comment Share on other sites More sharing options...
S.Violette Posted April 5, 2022 Author Report Share Posted April 5, 2022 Not sure if a Aux7/Pin 11 wire exists in a manual car. I used the Ign8/Pin 36 Evap purge option. Works great. Wired the ground for the Evap Purge to the 12V coming from Aux Fan Relay. Configured in system. Love the test feature in software. Quote Link to comment Share on other sites More sharing options...
Tyreak Posted February 21, 2023 Report Share Posted February 21, 2023 Do you have any pictures of how you wired ur engine fan? Quote Link to comment Share on other sites More sharing options...
S.Violette Posted February 21, 2023 Author Report Share Posted February 21, 2023 I tapped into the wire near shock tower. Harness is running down top of fender/hood line. I will try to post pictures. Quote Link to comment Share on other sites More sharing options...
Tyreak Posted February 21, 2023 Report Share Posted February 21, 2023 What color wire Quote Link to comment Share on other sites More sharing options...
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