Truck & SUV Questions & Expert Advice

Blinking Lights
Q: The dome lights in my 2003 Durango flicker on and off when all the doors are closed. Is this a short, a bad ground, or a bad switch?

A: Check the doorjamb switches, which are often simple gadgets mounted within the doorjamb. They get pushed in to break a circuit and turn off the interior lights when the doors are closed, and are spring-loaded outward to complete a circuit and turn on the lights when a door is opened. These are a common source of problems due to accumulated wear and tear inflicted every time a door is opened or closed. The 2003 Dodge Durango uses "door-ajar" switches, which are integral parts of the door-latch assemblies, located inside each door. These aren't so easy to test and/or replace and require removal of the interior door panel. Of course, there are several other potential causes of flickering lights. Each door-ajar switch sends a signal to an electronic unit known as the central timer module. This module--after evaluating data including but not limited to a door being open--makes the decision as to which lights go on, when, and for how long. In other words, today's systems are more complex, and your problem may be a switch, an electronic module, a relay, or a poor connection in a number of circuits. A qualified technician with the appropriate wiring diagram should be able to pinpoint the problem fairly quickly. In the meantime, try this: With the doors closed and windows down, hold each door and rock it in and out. If the lights flicker with the motion of one particular door, that door-latch assembly is most likely the cause.

Staying Legal
Q: Is it possible to unhook the catalytic converter on a 1998 Dodge Ram Sport pickup without any problems?

A: The Environmental Protection Agency prohibits the removal (or rendering inoperative) of specific emission-control devices, including the catalytic converter. The maximum fine is $2500, but there's more to it than breaking the law. The catalytic converter is an exhaust-system component designed to reduce three harmful emissions: carbon monoxide (CO), hydrocarbons, and nitrogen oxides (NOx). Your particular Dodge Ram, along with the majority of late-model motor vehicles, utilizes two or more oxygen sensors. One is located in the exhaust system between the engine and the catalytic converter, and another is positioned downstream, after the converter. These sensors read the amount of oxygen in the exhaust gases and send the information to the system's computer (powertrain control module). This enables the PCM to determine if the catalytic converter is functioning correctly by evaluating the difference in oxygen content before and after the exhaust is processed though the converter. A failure will light up the "Check Engine" light on the instrument panel, store a trouble code in the computer's memory, and prevent proper operation of the system. Sure sounds like a problem to me.