• Q. Help! My mechanic has fleas! My mechanic has a “garage dog,” who is very old and droopy. I think he has fleas, because after I got my car back, I’m getting bitten in my car! Now I need to get my air conditioner fixed, but I’m afraid to take it in, because I fear the fleas will get worse if I go back. Help! •

TOM: Here’s what you do. Start by sitting in the driver’s seat and fastening your seat belt. Note where the shoulder harness crosses just under your neck. That’s where you want to attach a flea collar so you can wear it from now on whenever you’re driving.

RAY: I think we can do better than that for you. First, you want to be sure that what you’ve got are fleas. But let’s assume you’ve seen them and confirmed that. The next step is to vacuum your car thoroughly. Use one of those thin upholstery attachments, and hit the seats, the carpet, the headliner and all the crevices you can find.

TOM: Then your vacuum will have fleas. So remove the vacuum bag, seal it up and dispose of it in a container outside your house.

RAY: Next: Chemical warfare. Even if you got every single flea with the vacuum — which you didn’t — fleas leave eggs. Which turn into more fleas. So if you don’t like the idea of using serious pesticides, you can start by using a borate-based desiccant, like Borax. That’s a drying agent that does a good job on fleas. Sprinkle it into the carpet and seats, and just leave it there.

TOM: Flea larvae turn into adult fleas in about three weeks, so you have to leave the stuff in the carpet and upholstery for at least that long before vacuuming it up. But I’d wait a couple of weeks longer just to be safe.

RAY: If you want to go all out, instead of the borate, you can use a flea spray or flea bomb that contains IGR, insect growth regulator, a hormone blocker that keeps the larvae from reaching the adult stage. I’d ask a local veterinarian to recommend an effective one.

TOM: And the final, but crucial, step in getting rid of fleas is to prevent re-infestation. The kindest thing to do would be to speak to your mechanic privately.

RAY: Tell him that your car was infested with fleas, and that it happened just after the car was at his shop for the day. You can say you’re not 100 percent certain the fleas came from the shop, but you know he has a dog, and you’re reluctant to go back until you’re sure there’s no problem.

TOM: This will give your mechanic a chance to take care of the problem, since you’re probably not the only customer who’s left his shop with something other than brake pads.

RAY: You’ll also be doing a service to his poor, old dog, who can’t be very comfortable if the garage is infested with fleas.

TOM: As for your air conditioner, I wouldn’t blame you for taking it to someone else for the repair right now. Check the Mechanics Files on www.cartalk.com for recommendations in your area, which come from other readers and listeners of ours.

RAY: Then check back with your mechanic in a few weeks, and ask him if he found anything. If he gives you a satisfactory answer and appears to have addressed the problem, you can start going back to him again. And if not, you can take your business elsewhere and send him a case of Hartz 2 in 1 for Christmas. Good luck!

• Q. My daughter has a 2001 Mitsubishi Eclipse four-cylinder RS model. Everything electrical died, and she was told that the computer is no good. Since the car is not worth all that much, we wanted to get another computer from the junkyard. However, we were told that would not work. They said each Eclipse computer is programmed just for that car, and we would have to purchase a new computer, for about $1,200. Is there truth in what she was told? •

RAY: No. In lots of newer cars, you cannot just take a computer out of one car and drop it into another car; it won’t work.

TOM: That’s partly due to the way the newer computers are wired. But making them difficult to reuse also helps reduce computer theft. As you found out, these computers are kind of pricey.

RAY: There is a method by which you can reuse these newer computers, but we’re not going to share it here, since that would only encourage computer thieves.

TOM: Which, in turn, would cut into OUR computer theft business!

RAY: But on your daughter’s car, and most older cars, you can buy a used computer. There’s no good reason not to. After all, the rest of the car is 10 years old —- what’s wrong with having a 10-year-old computer?

TOM: But first, make sure you know which computer it is —- there are several. Cars have electronic control modules for engine functions, and body control modules for the heater controls, power seat memory and other stuff. Then, once you get the right module, your mechanic may have to reflash it, because some modules contain “learned” information about the previous car. But that’s no big deal. “Used” is the way to go.

Got a question about cars? Write to Click and Clack in care of this newspaper, or email them by visiting the Car Talk website at www.cartalk.com.