Guys, I need your help.

While disconnecting 4 plugs on the back of the HVAC unit, instead of pushing pin (clip) on the bottom of the plug (like on all others) for some reason, like a fool, I opened up one of them instead of disconnecting it. Now I don't know which wire goes to which pin.

Connector (M40) for which I need pin to wire color layout have 10 pins and it is top left when looking from behind of HVAC unit.

First question:
Are pin/wire numbers assigned when looking at white connector from behind (where wires enter connector) or from front (which goes into black connector on HVAC unit)? I am guessing that pin 1 (Black wire) is on top right, when looking from behind of HVAC unit.

Second question:
I have 2 more wires than service manual stereo diagram (obtained from G35Driver) is listing on M40 wire-color diagram: Grey and Red with yellow Line. While M40 wire-color diagram is listing all pins 1-10 except pin 7 and pin 9. I have no idea what are they for or if Grey wire should go to pin 7 or pin 9.

This is on 2004 BASE 6mt coupe.

Thanks for any suggestion you might have.

 

its while looking at it from the proper way, when the harness is disconnected, not when the wires are removed...

in M40, 9 is earth (ground) black i presume

 

this is the schametic for M40


|10|8|---|4|2|
|09|7|6|5|3|1|

 

I made the same mistake on a different connector a few weeks ago. I got the 04 and 05 manuals and read them several times. I finally found a home for all the wires except two (like you.) Fortunately, I had taken a picture of the harness prior to disconnect so I could *kinda* make out the colors. I guessed right and everything worked.

BTW, since pin 9 on M40 is listed as ground, I would guess the grey wire if I had to on that pin. I can't find pin 7 color anywhere. Could that be a no-connect?

Finally, I see M40 color differences based on Nav vs no-nav. For instance page AV-64 shows different colors for pins 1,2,3,4,10 as compared to page AV-11 and following.

Finally, you probably figured this out, but any page with a picture of M40 on the bottom of it will have some information about some of the M40 wires. I had to use several pages to piece together the information.

The color code legend is on page GI-18. And I did find a typo in my manual on one of the wires. It showed G/R and should have read GR.

Good luck

 

After cursing yesterday, I paid for 1 day access today and then learned with voltmeter that Red with Yellow (R/Y) have 12V when lights are turned on (same as Red with Blue (R/L) which according to manual goes to pin 8), while Grey (GR or GY) wire have 0V and therefore it goes to pin 9 of M40, so R/Y must be pin 7 (not in manual!).

To complicate things, since I bought the car, I had problem with Illumination Control Switch (M7), down by VDC switch. It was always on max or if I rotate just a little, on min. Yesterday, with lights ON, I had no radio illumination, so today I took M7 switch off (it have same R/L and R/Y wires plus Black) and shortened for a second pin 2 (R/Y) and 3 (B). Now radio has illumination on max with or without lights being turned on.

I believe that M7 is no good and will try to obtain new one. I probably helped to end his life (fried it?) yesterday when I had GR on pin 7 and R/Y on pin 9.

Lesson learned – look before pulling and measure before connecting.

Thank you for suggestions.

 

If you still have access...

Service Manual Download program

http://pages.sbcglobal.net/jpsmith1...oDownloader.zip

Thanks to Johnboy.

I found by searching this forum and used it.

 

Link doesn't work

 

PM me with your email and I can send you the downloader file.

 

In short, fix is new Illumination Control Switch (M7) and also new fuse 71.

Long story is that 2 weeks after, when switch arrived, mechanic installed “new” switch (M7). When I noticed him checking manual, I told him my story and asked that repair ends here because I wasn’t ready for $95/h labor and asked him about moonlighting. He suggested that I might need new $1k BCM.
After studying schematic at home, I noticed that I have no tail nor parking lights, so I went to check fuses behind battery but hood wont open because mechanic left hood cable disconnected. Fuse 71 was blown. With new fuse, when lights are ON, illumination did not work (entire dashboard). Now I was back where I was two weeks ago. So more studying of schematic and testing of “new” switch, which measured same as old one (pin 2 had same voltage as pin 1). M7 is not rheostat it is potentiometer but it have some unknown 14-pin IC and large transistor. Only after I read Kpierson post about dimmer, I started suspecting that I might sill have OLD switch and not NEW switch. Parts department loaned me my “old” switch which I tested and than installed. Now everything works.

I just trashed 3 days of my time, but it could have been worse.

Reason of this writing is to let you that easiest way to test this switch is to connect 12V to pin 1 and ground on pin 3. If bulb in switch does not illuminate then switch is bad. Also beware of some mechanics and don’t think that service manual have no errors or omissions.