Here is a list of "hidden C5 features" that I found on the Internet

1. The little yellow "helper light" on the bottom of the rear-view mirror that illuminates the shifter area.
 

2. That you can put your key in the driver's door and turn it twice towards the front to unlock the passenger door and a third time to pop the trunk.
 

3. That you can pop the trunk and also pop the gas cap cover by pulling on metal lines hidden in the back.
 

4. That the little slotted cover on the dash behind the steering wheel is where the inside air temperature sensor is located.
 

5. All of the option codes are in the glove box. And if they aren't there, look on the underside of the rear compartment lid (passenger side, I think).
 

6. Tire inflation recommended pressures are on the driver's door (don't laugh, this comes up a lot).
 

7. The thing that looks like a little LED near the DIC buttons is a light sensor.
 

8. The thing that looks like a little LED near the defroster vent is a UV sensor for determining A/C usage

to compensate for the heating effect of the sun.
 

9. Your build sheet is in the front re-bar, your front bumper cover must be pulled for access!
 

10. When the engine is shut off, you can get the odometer reading by turning on the parking lights.
 

11. You can program setting #3 (both memory buttons at once) in the seat memory to run the seat back and steering wheel forward for getting in/out of the car with the engine running.
 

12. Reset oil life by pumping gas pedal 3 times (but not with the engine running).
 

13. Hold down RESET button while on one of the trip odometers and it gives you the mileage you traveled since last starting the car.
 

14. Hold down the Active Handling button for 5 sec. to engage "Competitive Driving" (2000 and previous years must be stopped.)
 

15. If you hate DRLs you can pull the e-brake ONE click and they go off....
 

16. Simply remove fuse #2 under the hood and your DRLs will be out permanently. Only thing affected is that when you unlock at night using the key fob your front turn signal lights and back up lights will not flash. You front turn signals will operate normally. GO STEALTH and extend the life of your front turn signal bulbs (changing them out is not picnic).
 

17. The side-view mirrors can twist both forward and backward, decreasing the chance of damage if struck.
 

18. If you pull the seatbelts all the way out while you're buckled in, they ratchet back in to hold you tighter into the seat (that's how the owner's video describes this feature)
 

19. The parking brake is self-adjusting... but depends on the car rolling or wanting to roll backward to work. Not mentioned in the owners manual (looked for it).
 

20. I didn't realize there is a red LED light on the left side of the radio so I had one installed to work when the security system is on. Someone told me to program the radio theft lock feature and that initiated the LED flashing. Now I have two of them flashing when the security system is on.
 

21. There is a release opening with a flap to let air out of the car when the hatch is closed.
It is located just above the driver side rear compartment, behind the panel.
 

22. There is a spot on the driver side just out of the middle compartment under the carpet for the lug nut key. You should have a compartment on the drivers & passenger’s side (in the trunk) and a center compartment. On the left (drivers) side of the center compartment, on the left side where the center cover fits, there is an 'indent' that holds the wheel lock key.
 

23. The bolts that hold the disk changer in the car, when installed from the factory cannot be removed. They have to be cut off.
 

24. You can ground your amp to a screw/bolt that holds the rear middle compartment to the frame.
 

25. If you turn on the headlights, then go to parking light position quickly, the lamps remain up but the headlights are not burning - this is for washing the lights.
 

26. If you have a 6-speed car you can pop the trunk when the car is running by lifting the e-brake.
 

27. On my Z06, the interior illumination light (the light that shines down from the rear-view mirror) is blue-ish and it will turn to a yellow color by sliding a colored lens over the lamp opening (no sheezot!) - I am not sure why this happens but the light does illuminate the console/shifter area.
 

28. Also not listed here, but the good Corvette Forum folks schooled me on this - if you go to comp-mode on the DIC, you can just hit reset to go back to displaying whatever mode you were in (fuel, odom etc.) and the comp-mode will still be activated.
 

29. If you have the passive entry feature: If you lock your keys in the car, wait a few minutes and then shake the car. That will unlock the car.
 

30. HUD has a shift light for manuals.
 

31. You can easily shift the M6 trans up or down without the clutch if you match revs. (Not great for longevity, however.)
 

32. You can eject the CD from the in-dash player without turning on any power. Don't even need key in the ignition.
 

33. The cruise will disengage if you purposely make sharp side to side turns while cruising at say 60-80 mph.
 

34. When the engine is shut off, you can get the odometer reading by turning on the parking lights.
 

35. HUD has a shift light for A4's too... it comes on during a WOT run just before it shifts!
 

36. With the engine off, opening the glove box automatically turns on interior lighting.
 

37. You have 20 minutes of auxiliary power after shutting the car off.
 

38. There is a key combination that can get the DIC to show any codes the car has thrown without autotap, etc. That combination is as follows:
• Turn the ignition key to the ON position, but do not start the car.
• Clear any pre-set messages by pressing the RESET button.
• Hold the OPTIONS button down, and press the FUEL button 4 times. This will get you into the CODES section of the DIC. The computer will automatically display all the codes your car has created. It will cycle through each code every 3 seconds. Any code that ends in H is a code that was registered previously but is no longer an issue.
• Once the computer has finished going through all of it's codes, press RESET to enter Manual Configuration mode. It should start with a module and show "NO CODES" or "# CODES".
• To optionally reset the codes once in manual mode, press and hold RESET until it displays "NO CODES".
• Press OPTIONS button to go to the next module.