90q20v won't start

[121040@comcast.net]

I am a former list member but dropped off because all of the Audis were running OK.  I'm back.

I was sitting at a traffic light the other evening and my early 1990 90Q20V just died and hasn't restarted since.  I had just come in from a fast run on the highway.  Fuel level is OK and I can hear the pump.  No loose wires that I can see.  I am going to try to pull the diagnostic codes but I am guessing it's the ignition module or something like that.  I have already installed a bulb in the Check Engine light socket so don't need the test bulb.  I tried to pull the codes this morning using the socket in the driver's footwell and the diagram on the 20v.org site and only succeeded in blowing fuse 21 so I am wondering if the diagram is labelled right.  I will check the Bentley before I try it again.

I have a 90Q 10v I can borrow the module out of to test it.  Are they similar enough that they will interchange?  Where are they located?  I recall that the one on my departed 4ksq was behind the glove box.  I peeked back there and couldn't see anything but A/C ducts so didn't go any further.
thanks,
Dave