Intro: Re-Solder Car Computer
If the electronic functions in your car are malfunctioning, a faulty control module is likely the cause. In many cases this can be fixed by inspecting and re-soldering the circuit board of the control module that controls whatever is malfunctioning. In this case I am repairing a body control module from a Cadillac Escalade, which controls the windows, radio, and other functions.
Step 1: Find and Remove the Right Module
To determine and locate the correct module that you need to repair, do a little research on the internet to match the symptoms with the module. For the 2000 Escalade, the body control module is located under the center console.
Step 2: Open the Module and Inspect the Circuit
Every module is open-able, some are harder than others, just be patient; and if you need to, use the internet to show you how to open your specific module. Once it is open, remove the circuit board and look at the side of the circuit that has all of the soldered pins sticking through.
Step 3: Re-Solder the Defects
Look at the condition of the solder on each pin, if there are visible micro cracks, you can re-solder the defective solder, and your module should work again if there is nothing else wrong with the unit. Apply the heat to the side of the pin, do not rest the iron on top of the pin, otherwise it will push the pin out of the board when the solder liquifies. Apply the new solder into the pool of hot solder that is on the board. Try not to hit the iron with the new solder, if you do, it's not a huge deal.
Only do this if you have a relatively steady hand. You don't want to accidentally connect pins with solder. Practice on something else first if you want to see how you do. A magnifying glass is a huge help. You don't need to be an elite solder-er to do this. I am using a $5 soldering iron, and 0.15" silver bearing solder, you could use a little thicker solder if you want.