Changed battery on 2001 olds silhouette and now the instrument panel and radio don't work. Any suggestions?

SOURCE: Replacing dashboard lights on an 2000 Oldsmobile Silhouette Van?

the light bulbs are not replacable unless you can solder, you have to replace the complete instrument cluster, get one from a junk yard 100 bucks.

SOURCE: Gas Gauge not working properly

First...how do you get 25 mpg...I get 21 or so!!!!  Additives will never work on this.  The price for the pump is $150-175 for an aftermarket unit.
I just did the tank job for the sender.  Get an aftermarket pump/sender.  DO NOT ORDER from RockAuto for this part...their listing is wrong.  They send the gasket...which comes with the replacement.  Replacing the unit is relatively easy:

• Have less than 5 gals of gas in the tank.
• Get the driver's side of the car in the air and support it.  
• Remove plugs to the left of the tank on the bottom of the vehicle
• Start car and allow gas pressure to subside...car will stall
• Remove the fill pipe from the left rear of the tank..there is a valve on the fill pipe which will contain all but a few drops of gas
• support the tank and remove the bolts that hold the tank straps and lower the tank.
• lower the tank and remove the vent hose at the rear of the tank so you can swing it out
• after swinging it out, prepare to remove the unit from the top of the tank retaining the connector snap ons for the new unit.  Clean the area around the pump to remove the possibility of contamination.  Tap the ring sharply counterclockwise to remove it from the tank.
• Remove old and install new, pressing the unit into the tank...be sure to use that new gaaket they gave you.  Tap on ring, swing tank back, reconnect hoses, raise and bolt up.  Plug in.
• Start the car after turning key and waiting for 15 seconds to start so pressure can build.

SOURCE: none of the instruments in

check the fuses

SOURCE: my olds silhouette security light came on and would'nt start

I had a similar problem. Check your battery, it is probably on the verge of dying. My problem went away when the battery was replaced.

SOURCE: 2001 oldsmobile silhouette traction corntol is off and ABS light

I agree with the post about the tail lights. And the symptom about the brakes on when starting was also helpful. When I took off my rear tail lights and removed the top light bulb (top of the 4 is closest to connector) then repeat starting the car the problem is gone. I have a whole drawer of these bulbs that I removed, not because the filament was burned out, but because the base (similar to circuit card edge connector) had heat damage and melted. I am not sure exactly what the problem is but I think there are multiple conductors in the fixture which are too close or get moisture shorts. Anyway I hypothesize the circuit for daytime running lights is leaking current into the brake light circuit, and it causes that module that controls traction control and ABS to declare a fault. When you start with foot on the brakes the brake lamp is pulled on (I don't know if switches hi or lo) so that module doesn't declare the fault until you release the brakes.

I put in new bulbs and it works fine for now, but I know it may reappear some day then I will repeat, disassembly of the fixtures and inspect bulb bases for heat damage and clean out and replace. That is what did the trick for me.

Thanks Fixya and all contributors