I’ve got a weird one for you. When I accelerate hard, the brake-warning light on my Mercury Tracer briefly comes on. I can’t imagine why this might be occurring. Do you have any ideas?

-Tommy Marak, San Jose, Calif.

This is an easy one. A peek at my Alldata wiring diagrams revealed three possible reasons for an illuminated brake warning lamp: a closed brake fluid reservoir level switch, a closed parking brake lever switch or a short to ground in the wire leading from the lamp to either switch.

Let’s start by checking the fluid reservoir level, which is an opaque plastic avocado-size container under the hood, inboard and below the left hood hinge. If somewhat low on fluid, the float switch might be intermittently closing due to the fluid rolling rearward during acceleration. Be sure to use only DOT-3 or 4 brake fluid when topping off.

If you find the fluid level is OK, ask a helper to watch the brake warning light (with key on but engine off) as you tease the float switch slightly with your finger or wiggle the wires leading to it. Should the brake warning light flicker, either the switch is faulty or the lamp circuit wire is chaffing to nearby metal.

I’d also check the parking brake switch for possible hair-trigger operation. Does the light illuminate the instant you raise the brake lever, or after several clicks? Does wiggling the lever side to side or smacking the console cause the light to flicker? If so a loose or faulty switch or chaffing wire might be the culprit.



My “98 Honda Civic went for its 90,000-mile service at 104,000 miles at a nondealer. The automatic transmission shifted OK, maybe a bit slow, if anything. Afterward, it shifts hard, both up and down. It’s a little softer when well warmed up, but still unacceptable. The repair shop has no idea what caused the problem. The coolant, transmission fluid, brake fluid, timing belt and spark plugs were changed and the valves adjusted. Any idea what might have caused the difference?

-Winston Barrows, Mystic, Conn.

It sounds as if your repair shop took the cheapo route and used generic Dexron III transmission fluid rather than Honda’s more expensive but necessary corporate fluid when refilling the transmission.

Virtually all modern automatic transmissions use Dexron III/Mercon transmission fluid, or a unique variant. Dexron is a friction-modified fluid. This means in addition to being a lubricant, the fluid contains additives giving the transmission’s clutches just the right “bite.”

A growing number of manufacturers specify their own version of Dexron, specifically tailored for the type of clutch material used or lubrication demands of their transmission. Use of a generic fluid may result in excessively firm shifts, or mushy, slipping shifts, which can dramatically shorten transmission life.

I’d recommend draining the transmission and refilling it with Honda-specific fluid as soon as possible.

Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose.