Volvo Repair: 1990 Volvo 240 Speedo/odometer, speedo needle, instrument clusters

Question
I pulled the instrument cluster today, because my odometer didn't work.  After I replaced the 25-tooth odometer gear, the odometer still didn't work.  Then I saw a loose red and white wire and, thinking that I had left it off, connected it to the two-prong male fitting on the back of the cluster that had the yellow wire connected to it.  When I turned the key on, the speedo needle buried itself and it no longer works.
I don't have a tachometer on this car.  I also don't have a wiring diagram for the instrument cluster or speedometer--my Haynes only goes up to 1986.
The question is, did I fry the speedometer head?  Can you tell me where I can get the wiring diagram I need?
Thanks very much,
Jake Manning

Answer
Jake, in a word, Yes, you cooked it.  That white red is the tach wire. You can thorow that haynes away.  Its toilet paper.  If you are interested, I make custom instrument clusters and Im sure I have a 90 around here somewhere. You seemed to have hooked up everything correctly.  Mark the red/white as tach so you dont blow it again.  Send me your Email and I will send you some samples of what I do.  Roger