I recently did a AW71 - M46 tranny swap in my '95 940T. Everything is great with the swap except I can't get the cruise control to work.

At first I had the wiring on the brake and clutch pedal vacuum switches wrong but now I'm pretty sure I have it right and the cruise still won't engage. I'm also sure I have the vacuum switches set at the proper distance from the pedals - I can hear the switches click when either pedal is pushed in a little ways.

The wiring diagram in my Haynes 940 manual (British) shows a wire coming off the automatic transmission control unit "B" and going to the CC Control Unit. It also shows that there's a wire that goes from the automatic shifter to the automatic transmission control unit "A" which tells that unit if the shifter is in either D,3 or L position (I think) by completing a ground. This leads me to wonder if the cruise on the automatics was tied into the automatic shifter via those control units so it couldn't be activated unless the shifter was in a forward gear. My diagram shows that wire from the shifter to control unit "A" as being Green & Brown but I have no wires colored like that coming from my old automatic's shifter.

Am I right about this ? Is the cruise system on automatics tied into the automatic shifter so that it can only be activated if the tranny is in a forward gear ? If so, which of the wires that went out to my shifter need to be shorted out or grounded in order for the cruise to work ? Or am I barking up the wrong tree here and need to keep looking at the pedal wiring and/or vacuum system as the prime suspects ?

Where are these automatic tranny control units located anyways ?

I hope someone can help me out here. This one's really got me stumped...

Thanks,

Roger