Q. I recently left my driver’s side window on my 2006 Audi A6 open during a bad rainstorm. My radio wouldn’t work, my high beams headlights didn’t work, and my parking brake indicator is showing malfunction. My radio turned back on after a day, but high beams lights and parking brake warning are still a problem. My low beam headlights function properly. Do you think this is a fuse or a relay?

A.  I suspect the headlight switch got wet and shorted. Looking at a diagram on the AllData technical database I use, the vent on the driver’s side of the dash looks like it could funnel water directly to the switch. There is no relay, it is part of the headlight module according to the wiring diagram. The module is located on the passenger side behind the glove compartment. The parking brake also uses a module that is in the trunk. I suspect the water caused an issue with the headlight switch. At this point, I would continue to let it dry out. If time doesn’t solve the problem, then someone with a professional level scan tool needs to look for trouble codes and see what is going on to further diagnose the issue. 

Q. I have a strange problem with my Toyota Highlander. When I go away on long drives in hot weather, one day the air conditioner is fine but the next day it will all of a sudden stop blowing air.  I can hear the fan going and a leak of cold air, but not enough to feel it without putting your hand right on the vent.  You can hear the fan speed up when you select different speeds, but the air flow doesn’t change. Usually, if I stop for an hour, it will start working again. Of course, it always happens when we don’t want to stop, like after lunch on our way home. This has been happening since we bought the car used, but other than this the car works great. Although the car has 286,200 miles on it, and I am planning on keeping it for another few years.

A. I would check the cabin filter first then next is checking the ducts and fan. Although you can hear the fan motor running, the actual fan may be the issue. I have seen some of these fans (looks like a hamster wheel) have broken fins which slows the air flow. 

Q. Here is my issue and need to know how to proceed. My 2023 Honda CRV Hybrid has 8000 miles. Under “Honda Care,” they will not change the oil until light comes on and is at 10% of oil life left. So, no service has been done since bought new Aug 2023 I took it upon myself to have the tires rotated. The tire person found a hole along the outer edge of the tread. A clean hole down to the tread about pencil-sized. Tech at Honda says that’s not covered under the new car warranty. He said to try and speak with the service manager. This hole definitely looks like a tire defect and not something that occurred while driving. Any thoughts? 

A. Honda is specific about at least yearly oil changes. Here is what Honda states “ If a Maintenance Minder indicator does not appear more than 12 months, change the engine oil every year.” So based on Honda’s own recommendation, it is time for an oil change. As for the tire, I would go to a tire store that carries that brand, if it is defective they can take care of it under the tire manufacturers warranty. 

Q. If I get an oil change with full synthetic oil, can I later add synthetic blend oil?

A. It is always best to use the same brand and type of oil because of the various additive packages that the oil manufacturer uses. The problem with a synthetic blend oil is you never know what percentage is synthetic. I use full synthetic oil and keep a quart in the car just in case. But yes, if you are on the road and find your car is low on oil and all you can find is conventional or a synthetic blend use it. Driving with low engine oil will most certainly cause engine wear. 

Q. My 2007 Subaru Outback will sometimes not start when I turn the key. The lights on the dashboard come on but nothing else happens. This recently happened so I turned the key back to off and waited a few seconds. Tried to start it again with the same result. The third try went the same way. I turned the key enough so I could shift to neutral and this time the car started right up. This has happened before, but it is weeks or even months between instances. The rest of the time the car starts fine on the first try and it runs great. In previous cases it would start on the third try. Any ideas on why this is happening? I use the same key every time and the car is old enough that there is no fob. 

A. There are a couple of possibilities. After testing the battery and voltage drop looking for poor connections, the next step would be the transmission range switch (neutral safety switch). Then the starter relay and finally the starter itself. I suspect the starter and by moving the shifter may be just enough to jar the starter to work again. The bigger issue is, this is all guess work unless a mechanic can catch the issue when things are not working. It is hard to fix something that is operating properly. There are some issues, that time is the best diagnostic tool.