Q My wife and I have a slight disagreement about our '02 Chrysler Concorde. I want to fix up the car with new tires, shocks, struts and a new timing belt. The car has 114,000 miles on it and has never had anything done to it other than brakes and regular maintenance. She says leave it and fix as needed. We have the money to make the repairs. What do you recommend?

A This is a no-brainer. New tires, shocks, struts and timing belt are routine maintenance -- not repairs. Rather than wait for something to fail, I wouldn't hesitate to try to pre-empt problems by taking care of any necessary or scheduled maintenance now and continue to drive the vehicle for several more years.

The 2.7-liter engine available that year uses a timing chain that does not need routine replacement. The 3.5-liter engine is fitted with a timing belt that, according to my Alldata automotive database, should be replaced at 100,000 miles. Assuming you spend $1,500 on maintenance now to cover routine service for the next three years, you're still well ahead of major repair costs or the cost of replacing the vehicle. If you're definitely going to keep the vehicle, do the maintenance now.

Q I own a 2004 Lexus ES330. The car has about 21,000 miles on it. Sometimes, when I'm driving, the wipers will go on. I have them set on "auto," but when this happens, I change the setting to "off" -- but even then the wipers will go on. This happens only rarely, but it is annoying. Any ideas about what might be the problem?

A Are the wipers on your Lexus equipped with the rain sensing system? If so, this may be the problem. The rain sensor is next to the rear view mirror mount. The fail-safe mode for this system activates the wipers in the intermittent mode when the switch is in the "auto" position or when outside temperatures are below minus 10 degrees or above 80 degrees. If it's not the rain sensing system, the wiper switch is suspect.

Q I have a 1999 Infiniti G20 with a strange door-lock problem. All the door-lock buttons repeatedly lock and unlock before stopping in the locked position. This happens whether the car is running or not. The driver side functions normally with either the key or remote when opening the door.

A First, check the voltage supply at terminal 11 and ground connection at terminal 16 in the "smart entrance control unit" connector, under the dash on the driver's side. My Alldata automotive database shows a step-by-step series of voltage checks for each door switch at this connector. Poor or intermittent connections at this control unit could be causing the power door-lock cycling you describe.

Motoring note

I'm sure you've noticed all the spectacular street rods, custom and collector cars and trucks motoring around the Twin Cities. They're all headed to Back to the '50s at the State Fairgrounds in Falcon Heights this weekend. With 100,000 fans and more than 12,000 street rods expected, it's the largest outdoor spectator event in the state put on and staffed by an all-volunteer organization: the Minnesota Street Rod Association.

The show runs Friday through Sunday and includes the Mecum auction, the Ignitors mini-show for youth rodders, gigantic swap meet and outdoor concerts each evening. For more information, log on to www.MSRA.com.