As most classic car buffs have learned, the majority of old cars come with their own lists of little things that have stopped working or gone missing over the years. Most of these minor issues have no effect on driveability or safety, so owners usually overlook fixing them. They focus instead on problems that would keep the cars from being driven, like brakes, suspension, and other mechanical concerns that might leave them sitting alongside the road. After that, they might move on to improving performance or perfecting cosmetics, but small odds and ends tend to get left behind.
Classic corvettes are no different in this instance. So as to help newcomers to the classic car world to avoid being caught off-guard, we’ve compiled a list of things that commonly do not work on C3 corvettes, gathered from our own experience buying, selling, and working on these cars for the past decades.
Common Components That Often No Longer Work in Classic C3 Corvettes
Burglar alarm – While GM had great intentions with the factory burglar alarm, it left a lot to be desired. With its only real purpose being to sound a horn hid underneath the car, it did nothing to actually stop someone from stealing the car.. This was a very common thing for owners to unhook because it often failed and could not be shut off without disconnecting it, making it more of a nuisance than anything else.
Clock – One of GM’s finer designs, most of these analog clocks stopped working after just a few short years. Beginning in 1981, the clock was included as part of the radio, fairing much better than their predecessors.
Tachometer – Between 1968 and 1974, GM used a cable-driven tachometer. This design worked great for the most part, and was fairly easy to repair when it broke. In 1975, GM switched to an electronic tachometer, which worked off of a circuit board fixed to the back of the tachometer behind the dash. Problematically, removing the dash on 1975-1977 corvettes can be tricky, so most people do not bother to replace the circuit board when it goes bad. Starting in 1978, the tachometer comes out through the front, so it’s very easy to replace the circuit board.
Cigarette lighter – Since they were used for things other than charging cell phones and GPS units, they are usually no longer in any sort of shape to charge or light anything. Since the battery is just right behind the driver’s seat, I personally use one of these in all of my corvettes.
Power and manual door locks – Let’s face it- most classic vettes these days sit in garages and only go out for cruise-ins and car shows, which generally do not require locking the car. So for the most part, the locks have not been used in years. This means the grease gets hard and gummy and does not allow the doors to lock or unlock. There are also plenty of owners who somehow lost the door keys over the years. Power door locks became an option in the 1978 model year. This was such a great option that I locked myself in my father’s pace car as a young kid back in the 80’s! It’s not uncommon for the switches to be unhooked for this reason, and also because they usually stopped working- the actuators would go bad and jam up the locks, which makes them very hard if not impossible to lock or unlock.
Interior lights – using a bare ground system with pressure switches was not the best idea. Generally the pressure switches get broken or corroded. This causes the system to either stop working, or stay on and drain batteries until someone figured out how to unhook the system.
Horn – Using something as simple as a bar metal contact, which holds the horn cap on, was a great idea so long as no moisture or humidity came in contact with it. Generally, this is something that can be fixed and may work for awhile, or may stop working soon after the contacts are cleaned. A lot of people just install a switch under the dash to avoid dealing with the horn contacts. Aside from the corrosion of the bar metal contacts, the horns themselves would often go bad due to moisture and debris, thanks to their position right behind the headlights.
Air Conditioning – Long story short, it very rarely works. Fortunately, you do have some options if you are set on having working A/C in your classic corvette. Click here to see the full blog we wrote covering all the issues, and options for solutions for AC in C3 corvettes.
Seat Belts – Here are some hard facts for you- These cars are 40+ years old. If you plan on using the seat belts, I strongly recommend replacing them with new ones. Usually the retractors are broken, but more importantly the material is 40+ years old and not worth taking a chance that they do not work when they are needed most. I have had great luck with Seat Belts Plus. They offer lots of different options depending on what look you are going for.
Radio – In the 1970’s and 1980’s, the radios that came standard in corvettes were top-of-the-line. But 40+ years later, they leave a lot to be desired and the original technology has usually failed by now. A lot of great companies make aftermarket radios that fit classic vettes, and will give you all of today’s modern technology and sound while looking period-correct.
Leaks – Yes, like all old cars, it’s going to mark its spot in the garage. Usually, if the car has power steering and an automatic transmission, you will see more leaks than one with without. I keep plastic under all of my cars and Pig Mat on top of that. Click here to read our full blog on corvette leaks.
Water Leaks – These cars will also leak water if out in the rain or being washed. This has been a problem since day one. In fact, GM actually put drain holes in the floors of the C3’s so the water could run out and not get trapped on the floor.
Cruise Control – Starting in 1977, GM offered cruise control. While it was an interesting concept for the time, it worked off of vacuum and was controlled by a transducer box that was attached to the speedometer cables. When the transducer box goes bad, and it almost always does, it takes out the speedometer and odometer. Not only does this kill the cruise control, but usually led to corvettes being driven without turning miles for years before anyone would either bypass the box with a longer single speedometer cable or go through the hassle to replace the transducer. Incidents like this are one of the many reasons why mileage is usually exempt on classic vehicles.
Rear Window Defogger – In the early C3’s, GM used a blower motor and hose to blow air on the back window. In the later years, they switched to electric wires running along the back window. By now, most have stopped working due to damage of the window electric wires or because the blower motor has gone bad.
Missing parts and pieces – As always, old things get lost over time. With corvettes, usually the first thing to go was the original paperwork. After that, the spare tire and possibly the spare tire carrier were done away with to reduce weight and noise. The jack was also removed for different reasons. A popular one was for ice and drinks to be stored in its place. Ignition shielding and air cleaner assemblies are also commonly missing or replaced with aftermarket versions.
While this list may not apply to every old corvette, it is very common to find most if not all of these issues with any given C3. You might also find other things not working that are not listed above.
All of these things can be fixed if so desired, with time and money. But for most people, it’s just part of the charm of classic cars.