My truck’s engine fan won’t stop running

How

AAA Northeast Car Doctor John Paul answers a question from a reader whose 2011 pickup truck has a fan that never turns off.

Q. My 2011 Nissan Frontier’s engine fan runs constantly. It would start when needed for cooling and air conditioning purposes. Since I’m pretty sure they’re all electric now, where is the switch or sensor located? My guess is that when it becomes faulty it goes into default mode and stays on instead of dangerously not working at all.

A. The fan in your Nissan and many other vehicles has multiple speeds. The computer controls the fan speed based on information from the temperature sensor. Unlike some other vehicles that use a separate temperature sensor for the fan and one for the computer, Nissan only lists one sensor. The sensor, relays (there are two), wiring, or the fan itself could be causing the problem. A technician with a scan tool will be able to read the temperature data as well as command the fan to turn on and off. This will help verify which components are working.

Q. I’m tired of being blinded by headlights. I’ve been driving for 50 years and these new cars have headlights that are just too bright. What can be done about this? They should be illegal.

A. Interestingly, most of the complaints I get about bright headlights come from people who can most benefit from better vision at night. At 60, we need three times more light to see than when we were 20. I’ve evaluated thousands of vehicles over the past 40 years, and there are certainly good and bad headlight designs. In addition to glare, our eyes are attracted to the brightest light. So when we see a brighter lighthouse, we tend to stare at it. Just as we need more light to see as we age, we also need more time to adjust to glare. Before about 1980, most cars had standard incandescent headlights, then cars switched to halogen lights and people complained. The problem was quickly resolved, as halogen headlights were relatively inexpensive and many drivers switched to halogens. Then brighter Zenon or HID lights started appearing. This was a very expensive option for luxury cars. Now HID lights are being replaced by LED lights and that’s part of the problem. Many drivers buy aftermarket LED bulbs, and these bulbs can be very bright and not legal for road use – but people buy them. Recently, the 40-year-old headlight rules were updated by the DOT/NHTSA to allow European-style headlights. One model is the Matrix light, I saw/tested them in an Audi. There are 13 bulbs on each side of the car and no traditional high/low beams. These lights provide incredible light but turn off the bulb/light segments when other vehicles approach. This design provides sufficient light to the side of the road and does not blind oncoming drivers.

Q. I recently saw a Tesla powered Toyota RAV4 for sale. The car was older, but it said it had a Tesla transmission. When did it happen?

A. I suspect what you may have seen was a RAV4 with an early Tesla battery (made by Panasonic). I remember seeing them at one of the big car shows around 2010, and at the time most people just thought EVs were a fad and Tesla was going to be nothing more than a brief mention in automobile history books.

Q. What things should I check or do to prepare my car for summer? After staying home for three years due to COVID, it’s time to explore our country. This will be my wife and I and our small dog in our 2018 Honda CR-V. The car appears to be in good condition and only has 40,000 miles.

A. Being a 2018 model still makes your Honda sound new, but it’s six years old and some maintenance and repair may be necessary. With 40,000 miles on the odometer, the car might need new tires (a great investment for a long road trip) and the brakes might be nearing the end of their useful life. Change the engine oil, air and cabin filters, check the battery (if it is original, simply replace it). Check all belts, hoses and coolant level and condition. If the brakes need to be replaced, replace the brake fluid as well. If you drive with a roof rack and also drive on mountain roads, change the transmission fluid before your trip and use only Honda fluid. Enjoy your trip and send photos.

John Paul is AAA Northeast’s automotive doctor. He has over 40 years of experience in the automotive industry and is an ASE Certified Master Technician. Send your question to Car Doctor by email to (email protected). Listen to the Car Doctor podcast on johnfpaul.podbean.com.