If an old T12 lamp magnetic ballast is replaced with a newer T8 lamp and electronic ballast, the colors will probably not match. What Happens When You Put A Higher Watt Light Bulb? So if you have a classic car with missing ignition components, don't hesitate to replace the coil and ballast resistor yourself. Over time, the ballast resistor can be damaged by normal wear and tear, so there are a few things to look for when you suspect a bad or failing ballast resistor needs servicing. If this happens, the professionals at YourMechanic will be able to measure the voltage coming from the ballast resistor and determine if you need a replacement. Magnetic It will overheat and burn out. If a ballast is replaced with the exact same type of ballast, the wire colors usually match. The most obvious symptoms will be the vehicle starts, but then immediately dies as soon as you release the key. You can find out whether the issue is with the ballast, starter or the lamp with our guide - Easy Fixes for Slow to Start, Flickering or Faulty Fluorescent Tubes. If the engine then starts and continues to run when the starter button is released, you’ve … If you are stranded by the roadside without test equipment and suspect a bad ballast, you can disconnect the 2 wires and temporarily reconnect them to each other (by-passing the ballast). This will not only give you a better attachment point, but also keep you from having to run wires all over the engine compartment. The best location for the ballast resistor to be connected is close to the coil along the firewall. Choose a … Typically a black and white wire would connect to the two wires on the light fixture. This simple system is easy for even the novice mechanic to wire. Step 2: Locate Ballast Resistor along Firewall. There are two kinds of fluorescent light ballasts: magnetic (old) and electronic (new). The watt rating on your light socket usually states the maximum wattage. Ballast Wire Colors. Testing a ballast with a multimeter/volt-ohm meter. Most of the times when people have problems with buying the wrong light bulb, it is because they bought a light bulb with a higher wattage than they were supposed to. In order to ensure that the issue is with the ballast, you will want to test it with a multimeter. Vehicle starts, then immediately dies. The job of the ballast resistor was to inhibit current to a level that would not overheat the coil. The old magnetic ballast is an inductance coil. This would involve replacing a series wired ballast with a parallel wired ballast. You would have to provide more info to be certain what your problem is.