instrument cluster: flashing indicator lights and bouncing needles

i'm having "ignition-type" problems as well...

my problem started about 2 years ago when the odometer stopped working...i took the car to the dealer and they told me it was probably an ignition switch problem, but they weren't sure...i didn't want to pay for a "maybe" so i let it go. later, all the gages and indicator lights started flashing and have only worked periodically ever since. most recently, the car decided to go completely "dead" when turning the key to the run/crank position. i decided that i should finally get a new ignition switch...so i bought one, but before installing it, i wanted to check my old one.

i've got everything apart around the column and the column dropped for easier access. the "white connector that everyone is referring to in previous posts has a little plunger on it that gets pushed when the key turns...this apparently controls the door chimes. anyway, i don't see any signs of corrosion or contact buildup on the harness anywhere. so i reconnected everything electrically just to see if something had been loose, and now i have "ignition" type power (radio, etc) with the key off and out and the driver door open?? does anyone have a wiring diagram of the switch itself (so i can check functionality)?

could i have a different problem that is causing all of this?

any help is appreciated!! (sorry for the long post)

oh, forgot to mention it's a '99 blazer, 2-door, 2-wheel drive.

update: i completely disassembled my ignition harness and was able to clean the contacts and get the vehicle to run again. however, it did not fix my gage cluster issues at all...all the lights still flash and the needles bounce around.

99 blazer, 2 door, 2 wheel drive, approx. 115k

as the title states, my instrument cluster isn't working properly at all. the indicator lights (HB, Service 4X4, Check Gauges, Battery, etc.) keep flashing and the needles bounce around or don't work at all.

i pulled the cluster and checked the circuit board and it appears to be fine - no obvious shorts or opens anywhere, no burned traces, etc. connector pins are fine and don't show any sign of arcing.

the issue started about 2 years ago (at ~65k miles) and the dealer said it was "likely" an ignition switch issue. i just did an ignition switch clean/repair today (for other reasons) and it didn't change anything with the cluster. any ideas where to check next??

does anyone know what controls the instrument cluster?