Why are My Headlights Dim? Find out with Voltage Test

Dear Doctor: I have a 2009 Ram 1500 pickup truck with 79,000 miles. Recently, when I have the low beams on and put on the high beams, all the lights go out, even the fog lights. Is this a switch problem? The headlight bulbs are less than a year old. The headlights are very dim as it is. Any suggestions would be appreciated. Sandy
Dear Sandy: The fog lights will normally go out when the high beams are on. First, remove the bulbs and check with a new bulb or test light for voltage. If there is no voltage you need to check all fuses, followed by checking the high beam switch for voltage.

Dear Doctor: My 2016 Nissan Rogue has vibrations in the steering column, gas pedal, and floorboard. The shop could not locate the problem. What should I do? It scares me that this is happening. Karen

Dear Karen: Vibration is usually caused from a loose serpentine belt, metal contact from exhaust or engine mount, or even a loose mounting bolt. Low idle speed is another possibility. At my shop, I would first put the transmission in drive with my foot on the brake pedal and raise the engine speed slightly to see if the vibration goes away. I would also start the engine, and using a large pry bar move the engine slightly while someone sits in the vehicle to feel if the vibration goes away. The technician can also disconnect the serpentine belt to see if the vibration changes.





Dear Doctor: Last winter I purchased a new Ford Explorer and by spring I noticed a musty mold odor. The smell got worse as the weather got warmer and I was using the air conditioner more. I have had it in for service three times to address the issue. The first service was in July and the remedy was to change the cabin filter. This did not work. In August the dealer used a moisture meter to check the entire vehicle and found nothing. The remedy was to use an ionizer for 48 hours. Again this did not work. I love the car, but I just can’t take the smell. Any ideas? Jim

Dear Jim: A musty smell does indicate water. We need to start looking for any water damage under the carpet and padding, as well as in the rear in any storage or underseat area. You may also want to get a second opinion from an independent shop. You should also contact Ford Motor Company directly through customer service.

Dear Doctor: I bought a 2008 Pathfinder with the 4.0-liter engine from a dealer with a two-year extended warranty. The car has 70,000 miles now but when I bought the car a year ago it had 67,000. The engine goes through three to four quarts of oil every 400 to 500 miles. I don’t see any blue smoke when starting the car. My local mechanic changed the PCV valve, and doesn’t think it is the rings or valves. I did some research and found valve cover issues with older Nissan engines but the 4.0. Any ideas on what to look for? Paul

Dear Paul: This is major oil consumption. If there are no leaks, then I would remove all of the spark plugs and see which ones have oil on them. My guess is the engine has bad valve guides or valve seals. If it were a piston ring problem, then there would be a lot of engine blow, which is emitted when the oil cap is removed and the engine is at idle.

Dear Doctor: My 2007 Infiniti M35 has 96,000 miles. There is minor leak in valve cover gasket, which gives off a burning smell. What additive can I use and how can I fix the leak? Your valuable advice will help me a lot. Subodh

Dear Subodh: There is no oil sealant for a leaking valve cover gasket. It’s not difficult to replace the valve cover gasket. The intake plenum does have to be removed on some vehicles for valve cover gasket replacement. You should also replace the spark plugs at this time. I recommend using factory gaskets and spark plugs on this vehicle.

Dear Doctor: I have a Cobra replica with a Ford FE 428CJ and a Richmond Street five-speed transmission. The car is equipped with an aftermarket distributor made by Summit and an MSD Street Fire ignition box. The distributor failed and unfortunately is no longer in production. Instead of trying to hunt down replacement parts, I opted to install an MSD billet distributor with mechanical advance. Should I go back to a vacuum advance for better drivability? Will the car idle better and run cooler with the vacuum advance? The car will rarely see wide-open throttle and is mainly for cruising around with short blasts of open throttle. Greg

Dear Greg: MSD makes a good product and most MSD products require a larger spark plug gap. Regarding the vacuum advance on the old-school distributor, if you elect to connect the vacuum hose to the distributor, then there should be no vacuum to the distributor at idle (this applies to 99 percent of old-school vehicles). The vacuum advance will not affect idle; it will advance engine spark under light load from quarter throttle and higher. When accelerating under heavy or full throttle there is no vacuum going to the distributor. You can try it connected or not, you can also adjust the base timing from 8 degrees (advanced, they go up 2 degrees at a time until the engine feels right). As for the idle being smooth it will depend on what camshaft the engine has.

— Junior Damato, Motor Matters

Copyright, Motor Matters, 2018

(Manufacturer photo: 2009 Ram)

Junior Damato is an ASE-certified Master Technician.

E-mail questions for publication to [email protected]

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