Q: I have a 2009 Dodge Caravan. The right rear brake light is not working. Turn signal light is not working. Flasher light is not working. The taillight is the only thing working. The right blinker arrow in the dash blinks fast. I changed the bulb, but that did not fix it. What is the next step before seeking professional help?

A: Your vehicle uses a dual filament bulb. One filament glows for taillights, the other, brighter one is activated for the brake and turn signal lights. The rapidly blinking turn signal arrow is the car's way of letting you know that there is a bulb out. But seeing as how you replaced the bulb, chances are there is a problem with the socket, the connection or the wiring. I'm afraid you'll have to turn to a pro for this.

The hole truth

Q: Why do higher-end manufacturers provide drilled brake rotors (particularly on performance cars)? I've asked dealership personnel, and typically I get a non-answer. I'm of the opinion that slotted rotors do a better job of relieving any built-up gas pressure. Certainly there is a cost involved over nondrilled rotors. Your thoughts?

A: Most people think that the drilled holes or slots in brake rotors are there to cool them. While this is not wrong, there is a better reason. Under heavy braking, the friction material on the brake pads can become hot enough to smoke, so you are right about relieving gas pressure. The holes and slots carry the smoke from between the pads and rotors for improved braking performance.

The ABCs of EPC

Q: The EPC light came on in my 2013 VW Jetta. I heard of other Jetta drivers having the same issue, but none of us know what EPC is. Can you please explain?

A: EPC stands for Electronic Power Control. If the EPC light illuminates, there is probably a problem with one of the vehicle's sensors, such as the throttle position sensor, brake lights sensor or any of myriad others. If it comes on, take your vehicle in for repair. If it's blinking, take it in right away.

Don't knock it

Q: I recently purchased a Cadillac XT4 with a 2.0-liter turbo four-cylinder engine. The owner's manual says to use premium fuel. I spoke with the dealer about using regular grade gas and was told that by not using premium, the mileage could be reduced and it might also cause engine ping. I don't want to use high-grade gas if it's not necessary. What is your advice?

A: Your car will get better mileage with the higher octane fuel than a lower octane fuel. That is because, should ping be detected by the knock sensor in its engine, the engine control module will back off the ignition timing until the knock stops. In effect, the engine is getting de-tuned, so your mileage will suffer.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to motormouth.tribune@gmail.com.