BMW - 1993 325i M50 TU Chevy - 2001 Camaro LS1 w/ T56 Location Number Color Function Verified PCM Plug Number Color Function Verified Works? X20 4 Black/Blue AC Clutch Yes ------------Red 43 Green/White AC Clutch Yes X20 6 Violet/Grey AC Request Yes ------------Red 17 Green/White AC Request Yes X20 20 Black Tachometer Yes ------------Red 10 White Tachometer Yes X20 8 Grey Check Engine Yes ------------Red 46 Brown/White Check Engine Yes X20 25 Blue Generator Status Yes ------------Red 15 Red Generator Status Yes X20 11 Brown/YellowTemp Guage 1 [1] Yes ------------- BMW "dummy" Gauge Connection ---- See Comment in Cell D8 X20 12 Brown/Violet Temp Gauge 2 Yes ------------- BMW "dummy" Gauge Connection ---- See Comment in Cell D8 Fuel Pump Relay ---- See Comment [2] Yes ------------Red 9 Green/White Fuel Pump Yes X20 5? Black/Grey? Fan Relay Control [3] No ------------Red 33 Dark Blue Fan Relay Control Yes Igniton +12V Relay ------ See Comment [4] Yes ------------Blue 19 Pink Ignition 1 +12V Yes Constant +12V to PCM ---- See Comment [5] Yes ------------Blue 20 Orange Constant +12V Yes Constant +12V to PCM ---- See Comment [6] Yes ------------Blue 57 Orange Constant +12V Yes OBD-II Port Connection ---- See Comment [7] Yes ------------Blue 58 Dark Green OBD-II Port Yes Cooling Fan Relay --- See Comment [8] No ------------Cooling fan Connection ---- See Comment in Cell D16 X20 18 Black/Yellow Starter Yes ------------Starter Trigger Wire Connection

The above diagram applies to both "Green" and "Blue" relays.

[1] Owner: Thanks to some great research by our fellow BF.C member BRAAP, it is now known that the OBD-II sensor is okay to use in place of the OBD-I sensor. Therefore, just buy an OBD-II sensor and pigtail adapter, and use it in the stock location! Also, I am going to relocate the Chevy coolant temp sensor to the passenger side block hole, so that the PCM can have temp readings as well. This sensor just plugs into the harness. [2] Owner: See below picture. Post 87 is connected to the BMW fuel pump wire (green/purple). Post 86 is connected to the Chevy PCM's fuel pump wire (number 9 on red plug, green/white). Post 30 is connected to constant +12V, and post 85 is ground. [3] Owner: I don't have this wire in my X20 but it's listed on the X20 pinout sheet that is otherwise accurate. Currently I'm planning on using the PCM as my trigger wire for the secondary cooling fan. More on this later. [4] Owner: There are two IGN relays, labeled "Green" and "Blue". Green has a 20A fuse, and handles the PCM & C105 connections. Blue has a 15A fuse and handles the Injectors through plugs C100 and C101. See diagrams at right and bottom of the page for further connection details. [5] Owner: This wire is connected directly to +12V on the battery block, no relay, just a 15A fuse. [6] Owner: This wire is connected directly to +12V on the battery block, no relay, just a 15A fuse. [7] Owner: See picture below middle. Attach this wire to pin number 2 on OBD-II Port. Pins 4 and 5 are ground. Pin 16 is constant +12V. [8] Owner: Relay is 40A with 185* SPAL temp switch in the radiator. (primary cooling fan)