Why are my headlights flashing on Dodge Durango
In the old days the headlight switch actually switched power to the headlights. Then car makers used the headlight switch to switch power to headlight relays and the relays actually switch power to the headlights. Well, kiss those days goodbye too. Chrysler now uses a Central Timer Module (CTM) to do some of that work. The headlight switch in Dodge Durango is just used to signal the CTM which lights the driver wants to control. The multifunction headlight switch communicates with the CTM and the CTM actually switches power to the headlights. When it senses a command for fog lamps it provide ground to the control coil of an externally mounted fog lamp relay located in the power distribution center.
When the CTM fails, it can result in flashing headlights or flickering headlights. Since there’s no actual headlight relay, most DIYers think it’s a bad multifunction switch as if it was the old days and the switch actually switched power. The truth is, this CTM can degrade and delaminate, causing all kinds of weird electrical behavior. You can get trouble codes for the CTM using a high end scan tool. On Durangos, it’s most often mounted on the left side of the dash or in the driver’s kick panel. Open it and examine the condition of the circuit board. Delamination will be pretty obvious. A new one will have to be programmed by the dealer.
In addition to controlling headlights, the CTM can control the following functions, depending on year and model.
Chime warning for:
key-in-ignition when the driver’s door is open,
headlamps-on when driver’s door is open,
seat belt warning,
antilock brakes (when installed),
low washer fluid
The CTM is called a central timer because it also acts as a battery protection system in some vehicles if the lights are left on and ignition is off. The CTM will turn off the lights after 15 minutes to avoid discharging the battery.
© 2012 Rick MuscoplatPosted on by Rick Muscoplat