How to Repair the Overhead Compass and Temperature Display on a 2001 Ford Explorer
In a Nutshell
For several months, the digital compass and temperature display gradually faded. Pressing the display buttons and tapping the screen temporarily revived the device, but eventually the fade was permanent.
Research and the experience of others suggested the root of the problem was a faulty cold-solder connection. Two resistors on the circuit board required cleaning and re-soldering.
The process of disassembling the display, cleaning and re-soldering the board, and reassembling the display required about 30 minutes of work; work that I expanded to 3 hours including research, battling the connector plugs with clumsy fingers, and extra trips from house to truck for forgotten tools. Various estimates for completing the job ranged from $89 to $180++.
Most patient do-it-yourself(ers) can complete this task with moderate ease while saving money and learning valuable skills in the process.
Several online forums confirmed my suspicion about what was causing the digital display screen to fade to blank. When the fade can be temporarily repaired by pressing or tapping on the unit or the display, a loose connection is the culprit. Eventually the connection degrades and a permanent fix is necessary.
I am not a proficient handy-man. The idea of taking things apart that I might not put back together again generally intimidates me. If this sounds like you, take heart. (Caveat. Continue at your own risk. The author is not responsible for permanent dis-assembly, damage, incapacitation, lost parts, or burned skin caused by spilled cups of coffee resulting from this project.)
Generally, anything that you can imagine was assembled by a person or machine can be reversed, except for components permanently glued, molded or riveted into place. Fortunately none of the exceptions apply to this project.
My Sportrac has a sun-roof which is framed in the ceiling by a thin plastic molding. When the molding is pulled gently away at the aft end of the overhead console, a black tab is revealed. Pulling down on the tab will begin to release the console from the ceiling. Slide your fingers into the gap until you are 3/4 of the way toward the front. Next pull the console firmly to release the two tabs that secure it to the ceiling.
At this point the console will be dangling by the main electrical harness and the sun-roof motor plug. Disconnecting these plugs is simple, but not necessarily easy depending on your patience, dexterity and tools available. The harness is mounted on a slide release which is very easy once you figure out which way to slide it. As for the motor plug, I would recommend unscrewing the Torx screws and remove the plug and switch, as this will enable you to release the tension clips more easily.
With console in hand, you can now relocate the project to a work table. Plug in your soldering iron and set aside. Remove all 13 Torx screws and separate all of the console components. Unplug the display harness from the white housing and split open the housing by carefully prying the 4 tabs on the outer edge. At this point, the housing, the main harness, and the overhead light harness can be set aside as one unit, with the green circuit board remaining in front of you.
Refurbishing the Circuit Board
Several online forums I searched pin-pointed two resistors labeled "510" as the most likely cold-solder culprits. These resistors are designed to step down the voltage required by the display and do so by dissipating energy as heat. Like many devices, this printed circuit board, made in Mexico, has cold-soldered joints that use very small amounts of solder. Time, age, heat, vibration, chemicals from smoke and other factors cause these joints to fail.
In this case, the faulty circuit was not visible to my naked and untrained eye. I marked the solder points with a Sharpie and found that the resistors were secure. But the experience of other owners gave me faith that re-soldering the resistors would solve the problem.
A pristine surface and solder joint is critical to a successful repair. Using a Q-tip and 70% rubbing alcohol, I thoroughly cleaned the resistors and the solder pads. I own a medium heat soldering iron with a pencil tip. I thoroughly clean and tin the hot tip by dipping it in soldering flux, brushing the tip against a wet sponge, and then applying a small bead of solder to the end of the iron.
Using a toothpick, I applied a small dab of flux to the solder pads. Heating the flux and the pad without additional solder served to "clean up" any imperfection at the old joints. Use care not to burn the circuit board, melt the resistor, or add more debris. 2 seconds of heat should be enough. After the hot "clean up", I repeat the rubbing alcohol routine. Just prior to soldering, I dab a small amount of clean flux at the joint to promote smooth flow.
Now is time for the ultimate step. Applying a fine string of silver-bearing solder available at Radio Shack, I meet the tip, the pad, and run the solder at the joint for 2 seconds. Pulling the solder string away, I then "paint" the pad with the new solder for 1 second, leaving a smooth surface. After the joint has cooled, I repeat the rubbing alcohol routine to remove all flux residue.
Prior to reassembly, it makes sense to test your work. Plug the display harness directly into the circuit board. Gather the board, the overhead light harness and the main harness and carry to the vehicle. Plug the main harness into the main buss and allow it to dangle. Start the vehicle and see if that fickle display is working again. If so, congratulations! If not, you may need to repeat the soldering steps again, or even apply the same technique to other solder points on the board. Persistence will pay off.
In my experience, putting all the components back together was the simplest and easiest step. Start with the forward end and work toward the aft end of the console, securing the Torx screws. I offer one suggestion relating to reinstalling the overhead light within the console. Prior to plugging into the main buss, close your vehicle doors, turn the auto light fader off, and ensure the dome light is off. When the main buss is plugged in, turn on the vehicle and ensure that the console light switches function properly.
This article should be useful to all vehicle owners as it relates to troubleshooting vehicle electrical faults where a circuit board is involved.
Searching articles like this one will often guide you through the important diagnostic and dis-assembly steps. From that point on, its always about solid soldering.
I hope this was helpful to you. I have provided links to several sites that helped me along the way. Best of luck.
A Helpful Site I Visited During the Repair
- Explorer Forum Solution for Fading Overhead Display
I discovered this very instructional link half-way into my project. I would have preferred to start here and saved some time.