DEAR CAR TALK: I have a 2002 S10 Chevrolet truck that very often won't start when the weather is damp — summer and winter, in the garage or out.
Blowing under the hood with a hair dryer sometimes does the trick, but it's not convenient.
I have had it in to a couple of shops for repair, but they can't find the problem. I have had the battery and the distributor cap replaced. Any other suggestions?
— Caroline
DEAR CAROLINE: You need to install one of those big, car wash car dryers in your garage.
Then, you'll just flip the switch, and the car, the garage, and probably the whole driveway will dry out in no time. To save time in the morning, you can even stand under it and dry your own hair. As long as you're OK with a severe "down-do."
I'm going to suggest you try a new set of spark plug wires. That's the most common culprit when it comes to older cars that won't start in wet weather. The distributor cap was a good guess, but obviously that wasn't it.
In older cars like yours, here's how the electrical stuff works: When it's time for a cylinder to fire, your distributor directs a high-powered jolt of electricity through the spark plug wires, to the appropriate spark plug.
The spark plug uses that electricity to create what? A spark! A big spark.
That spark is hot enough to ignite the fuel and air in your cylinder, and that's what makes your engine run.
What typically happens with older spark plug wires is that the insulation surrounding them breaks down. And since water is conductive, when there's moisture in the air (or perhaps even condensation on the wires themselves), electricity leaks out on its way to the spark plug. If enough of it leaks out into the moist air, there's not enough power left to make a good spark, and your car won't run.
In fact, if you open the hood and get a friend to try to start your car on a damp evening, you can sometimes actually see a blue glow of electricity coming off of old plug wires. That's your power leaking away.
So, try a new set of spark plug wires. And don't be cheap. Either go to the dealer, or ask your mechanic to get you a set of OEM (original equipment manufacturer) plug wires. They're worth the investment.
If that doesn't fix it, then a bad coil would be my next guess. But at that point, you'd be guessing, which can get expensive.
You'll want to seek out a mechanic who's a little more interested in helping you than the last two shops you visited. If you can't get a good recommendation from a friend or family member, pick a top mechanic from www.mechanicsfiles.com, where our readers and listeners have shared the names of their favorite repair people.
Good luck, Caroline.
DEAR CAR TALK: I have a 2013 BMW X3 with a fan-speed issue.
As I am driving along, the fan speed will jump around randomly, going from a high setting to a low setting, shutting off entirely, then turning back on. The fan will usually function normally for about 20 minutes of driving before going haywire.
At first I thought it may be due to a faulty blower motor regulator. When I took the car to a local shop, they said it was a software issue, which they said they corrected.
But soon enough, it was misbehaving again. Any suggestions?
— Jyoti
DEAR JYOTI: I suggest you think of it as an optional variable speed fan, and try to enjoy it.
It could be the blower motor itself, but before you go there, I'd try replacing something called the final stage resistor. That sounds like the lead role in an end-of-the-world movie, but it's actually an electrical part that regulates the fan speed.
Almost all heating and cooling fans operate by using resistors, which vary the amount of electricity that gets through to the motor.
Let's say your switch has four settings: "off," "one," "two" and "three." When you set the fan on "three," the highest speed, there's no resistor used. All the current passes through to the fan motor, and it runs at its highest speed.
When you turn it down to setting "two," a resistor engages, limiting the amount of electricity going to the fan. When you set it on setting "one," an additional resistor cuts the power even more.
So, your final stage resistor could be shot. And since electronics are often affected by heat, that could also explain why it works fine for 20 minutes and then misbehaves.
Ask a mechanic who is familiar with BMWs to try changing out your final stage resistor. It may cost you $150 or $200 bucks — or, as BMW refers to that amount, the ante. Good luck.
Ray Magliozzi dispenses advice about cars in Car Talk every Saturday. Email him by visiting cartalk.com
Style on 08/17/2019