Admiral Akhtar Posted February 14 Report Share Posted February 14 Hello, Hoping someone can possibly help with a strange issue. I'm helping a friend with his Plug and Play ECU on his E36, and have made some wiring adjustments to suit the Turbocharger. Namely adding a Boost Controller, Electric fan and feeding the Wideband Analogue signal in via the expansion loom. The issue we are experiencing is with Aux Out 4 on Pin 46 of the BMW Engine harness By Default it is configured to run the Fuel Consumption gauge on the cluster, but I have rewired it to drive the earth side of the fan relay trigger I have reassigned the Aux Out to the engine fan, cleared the GP PWM table that was previously setup to run the gauge, and configured the engine fan to kick on at a set temperature All of this works fine when the Ignition is on, and when the engine is running, but as soon as you remove the key and the car is switched off, the fan turns on as if the pin is pulled to ground. I thought it may be a wiring issue at first, so I tested with just this wire disconnected and the fan stays off, then I Pinned it directly to the pin on the ECU in case there was a branch off in the loom to somewhere else that may be grounding it, but still no joy Can someone please advise how we can rectify this? or is it an issue in the firmware for the plug and play ECU itself? Quote Link to comment Share on other sites More sharing options...
Vaughan Posted February 14 Report Share Posted February 14 Is the other side of the fan relay trigger wired to constant power instead of an ignition switched power? Quote Link to comment Share on other sites More sharing options...
Admiral Akhtar Posted February 15 Author Report Share Posted February 15 The other side of the trigger is connected to a switch live source taken from another relay in the fusebox Does this suggest the ecu will ground out the Aux outputs when switched off by default? Quote Link to comment Share on other sites More sharing options...
Endurance_Racer Posted February 15 Report Share Posted February 15 This is exactly what that means. The ECU will ground them. The relay must have power to it. So I suggest you make sure that the power is completely disconnected from the relay. Quote Link to comment Share on other sites More sharing options...
Confused Posted February 15 Report Share Posted February 15 Yes, the aux outputs will be grounded when the ECU is off. This is clearly explained in the Help, even with diagrams explaining how/why! One reason why Link's documentation is one of the best! Quote Link to comment Share on other sites More sharing options...
Vaughan Posted February 18 Report Share Posted February 18 In this particular case you are actually partially powering up the ECU with the 12V through the relay into the Aux 4. If you need to have a constant feed on the other side of the relay trigger then use a spare ignition or injection pin rather than a standard Aux pins as standard Aux pins backfeed. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.