My brake and all back lights went out. Sometimes my radio suddenly goes out what should i do 2000 cadillac catera

you have a loose connection check your grounds under the dash an to radio

so you start the car and the radio will not work? but the radio works with he door open and key off? its normal to turn the car off and the radio play until you open the door.

K134 Multifunction relay is on the driver side, inside the dash above the driver's left ankle (area). (2) panels need to be removed below the steering column to access this area. The first is a panel that matches your dash. The second is a cardboard panel with foam padding on it that encompasses the arms holding the brake pedal and accelerator. You'll then need to lay on your back on the floor board, head in first. Look for a gray box about 3" square by 1 1/2" thick. Push it 'up' off of it's mounting bracket to release. Unplug the wiring harness. Plug in new relay and re-mount.

K134 Multifunction relay is under the dash on the driver side. When sitting in driver seat, above your left ankle, it is located behind a cardboard panel. Replacing cures many problems with the Bose radio, sunroof, gas and trunk releases, fog lights.

check for a short.

Please see my tip at http://www.fixya.com/cars/r5925550-dead_battery_troubleshooting . These are generic instructions. If you get stuck or need specific instructions for your car, please get back to me with model, year and engine info.

the speed sensor in the trans could be the culprit I would have the wiring inspected first though

there is a big chance that your sensor is nedd to be replaced

K134 Multifunction relay.

I have a 2000 Catera that when I changed the electronic brake control module all warning lights went off, speedo and odo worked. New EBCM is $2000 Cdn I got mine used for 170. also it can be re built at modulemasters.com for $160. Not sure about the dash light tho.
Rob

It's most likely the breaklight switch. it's a common problem in the cateras.

http://www.autozone.com/autozone/catalog/parts/partsShelf.jsp?categoryDisplayName=Electrical+%26+Lighting&fromType=parts&fromString=search&parentId=cat30065&currentPage=1&filterByKeyWord=switch&isSearchByPartNumber=false&navValue=15700132&categoryNValue=15799999&fromWhere=&itemId=prod61274&displayName=Stoplight+Switch&searchText=switch