If the oil level is OK, then either the oil pump or the oil sending unit is bad.
Bad oil sending unit, or bad oil pump. how many miles? if it's up around a 150,000 it could also be worn main and or rod and or cam bearings.
If the "side lamp" is located in the headlamp lens assembly, check out the "Related Questions" below for lots of detailed help
Check break liquid level. I did it, and its works! Cicipapa
This is really not an answer but I drive a 2001 Suburban and I have snapped the cover off and unscrewed the module. It is only the odometer that is not visible but when I slip the module out the thing is visible. On a cold day not long ago I cranked my truck and the odometer came on for a minute and went out again. I think the wiring is loose but it is difficult to see behind the thing.
Check the fuses then check the brake light switch.
An incandescent lamp can be used to check continuity of a circuit.
Low Oil Pressure Warning. Check fluid levels
A 2004 Chevy suburban should still be under warranty,unless you have custom lights, you can take it to the dealership and have fixed for free.
According to the 2001 Ford Mustang Owner Guide : Tail lamp , Brake lamp , Turn lamp takes ( # 3157 K bulb )
House of Mouse - 2001 Donald's Lamp Trade 1-10 was released on: USA: 24 March 2001
LED desk lamp. Nowadays this type of desk lamp came with modern feature such as power level feature where you can adjust the power level to suit your task.
possible wiring short in headlamp switch. remove dash cover remove screws holding head lamp switch check wires may have a burnt look to them if so replace wiring pig tail and switch. or trailer wiring if equiped could be shorted to ground on tan wire tan is park lamp or running lamp.