Restoring Readability To This LCD Wonder

When the Corvette C4 appeared in the early ’80s, it was seen as a technological advancement like today’s mid-engine Corvette. It took a world with storms, and the ability to approach a 1g lateral acceleration by an ordinary human being put a smile on the face for more than a decade.

GM wasn’t entirely sure that LCD dashboards would be produced, so it commissioned one of its subsidiaries to build an analog gauge just in case it was needed. Only about 50 units were produced but most were destroyed; one is at the National Corvette Museum and this one appeared on eBay a few months ago.

Owners of the 1984-1989 model were immediately met with the Corvette dashboard (for the time) with a stunning light show from the LCD gauge that propels you forward to 21st century, even before cars started moving. While the light show through the steering wheel was a great feat for the era, after all these years, it usually shows the need for touch ups.

corvette dashboard

The C4 dashboard goes into test mode when the key is first turned on and all areas of the dashboard light up. You can see the bottom of the last digit next to the speedometer is starting to fade. Over time, the entire gauge panel can be affected.

Luckily, companies like Batee Electronic Parts and Repair make it easy for enthusiasts to turn on the dashboard light on their Corvette C4. Bryan Thompson, owner of Batee.com offers plenty of necessary parts and plenty of videos to address any issues someone might have with their C4 dashboard. Batee also offers restoration services for those who prefer to entrust the work to someone more experienced. We prefer to do our own thing. and we reached out to the folks at Batee.com to restore factory functionality to our ’85 Corvette dashboard.

Corvette Dash Trouble Area

Although electrical components don’t move like many mechanical objects, they can still wear out or be affected by age and weathering. One of the most common problems with the Corvette C4 dashboard is when the dashboard lights up clearly. After time, the number is no longer legible. After running out of fuel (twice) because we couldn’t read the “Reserve” warning, we knew we had a problem.

Our gauges are fully lit, but you can see how the numbers disappear beyond the polarizing film test strip Batee shipped with.

The Dash C4 has a special polarizing film on the face of the gauge that allows the numbers to be legible. Over time, sunlight and heat reduce the film’s ability to properly polarize light. Living in Florida makes this a real possibility. Like our C4, you may see small segments of your Corvette’s dashboard go blank as the damage spreads across the gauge surface.

This film adheres to the windshield facing the driver and over time, heat and sun reduce the film’s ability to polarize the light that enters through it. You can see in the second photo how the film is completely gone.

If you think the polarizing film is to blame, you can put on some polarizing glasses and see if the gauge comes back to life. Batee offered a replacement film for the gauge glass and sent us a small sample so we could test the gauge cluster to see if it was a problem with our gauge. Formerly.

Another area that can be a problem is when the backlight flashes or doesn’t respond to changing outdoor lighting situations. There are several reasons why this could be happening and Batee again, help explain the problem, and how to fix it. They also offer the necessary photocells, custom connections, as well as the right bulbs to rebuild your dashboard to be better than new.

Start by removing the back panel. The odometer assembly and two logic boards are screwed into the gauge housing and hold the other in place.

Even electronic marvels are still prone to mechanical problems. The instrument’s power supply board can fail, turning the dashboard of your Corvette into a useless black void. Batee has created an updated power supply to cope with failed power sources and even improved its performance from the factory version thanks to advances in electronic technology.

The bottom board holds everything in place. Remove the screw and lift it carefully. Underneath, you’ll find the holders for the elastomeric couplers, light spreaders, and color filter sheets. Beneath all of that is a glass pane of the measuring surface.

The way the boards in the dashboard are joined together allows it to warp over time which can make for a poor connection. The tiny motor that controls the odometer can fail, the bulb can catch fire, and even the glass plate that forms the face of the gauge can be damaged and shattered.

Crush Corvette Dash

After you remove the gauge cluster and remove the back cover, you will see the cluster is built in layers. Before disassembling, it is best to remove the odometer assembly and set it aside. There are two control boards stacked on top of each other with 12-pin connectors that route power between them. The first board also contains the power supply board and is held in place with small screws. By removing the screws and carefully working the 12 pins from the board, you can then remove the top board.

Elastomeric coupler is a nice name for this pink block. They transfer control current from the inner logic board to the glass panel on the measuring surface.

The bottom board is sensitive to static but needs to be removed to fix our fade gauge. Carefully remove the screws holding the second board in position and place it where it will not be damaged. Hold the board by the edges just enough to release it and set it aside.

There are several components held in place by the inner board which can now be removed. Your Corvette dashboard has a plastic housing that holds the measuring surface in place and contains elastomeric connectors (pink rubber blocks) that you might find stuck to the gauge glass. After you remove the plastic case, you can remove the light spreaders for each measuring surface, as well as the color filter sheet that gives each gauge its color.

Corvette dash

The color filter sheet gives each face its own color meter as light passes through it. Carefully remove the sheet and set it aside so it doesn’t break.

At this point, you can carefully remove the glass panel (measuring surface). The pink elastomeric connector can be carefully peeled off the glass. Be careful with this, as you will need it for reinstallation. You don’t want to rip them off.

Polarizing Film Replacement

Looking at the glass plate, you will see one side is painted and the other side is polarizing film. Work no peel off the painted side. Batee offers black paint with its kit to repair paint that may have chipped or damaged over the years. Light will see through where there is no paint, and also, you don’t want to get paint where it shouldn’t.

One side of the glass has a polarizing film, the other is painted. Don’t peel the paint off! Batee offers pre-cut sheets of polarized film to replace the old, dried up original film.

On the other side of the glass, you may notice a faded polarizing film, which is easily removed with a small razor blade. Place the sheet of glass on a sturdy but secure surface, not a towel. You want something that won’t damage the painted surface, but also maintains even pressure on the back so the glass doesn’t shatter.

Polarized film is directional. The batee marks how the sheet should be installed. Notice the difference when installed incorrectly in the first two photos. The last photo shows the difference between the new meter face (left) and the old meter face (right).

You can then clean the glass with a glass cleaner to remove any residue. Polarizing film is directional, so it is important which way you attach it. Batee has marked film for easy installation. If it is installed incorrectly, it must be removed and replaced. Double check orientation before applying!

Connector Correction

As mentioned, some problems are caused by oxidized connectors or cold solder joints losing continuity. One of the main culprits is the 12-pin connector. The joint, where each connector meets its respective board, can be a cold solder joint and where the pins slide into the female side of the connector can become oxidized or carbonized.

Cold solder joints and joints between two boards with 12-pin joints can cause problems. Cold solder joints, such as the second from the right in the lower left photo, can be repaired by removing the old solder and re-soldering the joint.

Thoroughly inspect each pin as well as any solder joints on both boards. If you need to replace a connector, or if you need to re-solder a joint or two, you can use a solder wick to remove the old solder. Then just re-solder the connection to be like new. Check each connection thoroughly, because you don’t want to have to do it again.

Photocells (the black round thing in the first photo) can also be problematic. Batee offers a replacement, which can be soldered in place of the old one right next to the 12-pin connector.

Identifying a problem with your particular Corvette dashboard will tell you what components need replacing. Batee has a great set of videos to help you out. Other components such as the photocell may need to be replaced. In each situation, simply remove the old solder and replace the component.

Installing the C4 Dashboard

Replacing the components into the gauge housing is the opposite of disassembling it, but extreme care must be taken to make sure the glass pane is properly seated in the housing before you tighten the screws holding the inner board in place. They can easily break or crack if the boards press on them unevenly because they are not placed properly.

There are tabs for aligning the glass. Make sure the glass is fully seated, then install the color filter and plastic holder that secures the elastomeric connector.

When installing the elastomeric connector, you will notice that they are different sizes. Batee recommends marking the position of each pink connector so that they return to the same slot and orientation when they exit. You can reinstall the connector after the glass pane, color filter, light diffuser, and plastic housing have been installed.

Make sure the glass is installed properly. Batee offers Xenon or LED bulbs to replace outdated factory units. They are much brighter!

You’ll also want to make sure the 12-pin connector is cleaned and installed properly before installing the top board. It should slide and make contact with each of the pins. Otherwise, the gauge cluster will not function properly.

Corvette dash

When replacing the outer board, ensure that the 12-pin connector is seated properly on the female side of the joint. If all the pins don’t make good contact, they can go up and stop working.

Once everything was reassembled and the backplate was secure, we went ahead and installed the gauges to try it out before reassembling our Corvette dashboard. This way, if there is a problem, we can easily delete the gauge cluster and find out why.

We cleaned the area before installing the cluster. We installed it and checked everything before installing any other interior panels to make sure they are working as intended.

We love seeing all of our gauges come to life and now we can see exactly what all those colored numbers and bars are trying to tell us! We no longer have to live in fear of running out of gas in our Corvette C4. At least, not because our gauges weren’t trying to warn us!

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