my wife drives a 1994 Suzuki Sidekick JX just went over 100000 miles and service engine soon light came on the moment it turned 100000 miles. I tried the fix I've found in many other forums: disonnected the negative connection on the battery to clear all codes. light is still on.

question?: how does a person read the codes? special tool? where can I get one?

there is a swich usually mounted on the steering column behind the plastic trim. flip the swich and the service engine light will go out. If its not ON the steering column, look around that general area, thats most likely where it will be

Also there is a way to read the codes without a scanner, there is a 4 prong plug next to the battery, put a jumper wire between termanals 2 and 3, turn the key to the on position and the engine light will flash, count the flashes between each pulse and you have your engine code

To narrow it down, it's actually behind the driver's side in dash speaker. You can take the speaker out and feel around for the switch, or, if you have small hands like me, you can reach up and behind the dash and feel around next to the speaker for a small switch.

Heather

I had the same prob with my samurai  87 , except then it was a sensor light . I took it to a mech shop and they they said they checked the codes .. but there waasnt anything , but they said the light comes onn after 60,000 miles or so (might be more on the newer ones)
anyway all they did was hit the reset switch . and it is (on mine )under the steering colum under that steering colum panel , looks like a light switch .. I would reset it like that and if the light came back on , you have it checked out .. cost me $65 for them to resetit .. anyway good luck .