Mike you are right, I only had a 2000 manual.....you need a wiring diagram to see if it'* a direct ground or serial data....

I had this checked by a reputible garage but I didn't ask how they checked the ciruit. They did say it wasn't the bulb and they couldn't find anything wrong. I live in NJ and it is required for state inspection that this indicator be working to pass. I did just check the gas cap and noticed the rubber seal is cracked pretty bad, going to replace, who knows, maybe I'll get lucky for a change. Still searching for an answer, any ideas are welcome. Thanks

I finally got around to pulling the instr cluster and found someone had stuffed the pockets where the leds for the check engine with pieces of a paper towel! Now I have to figure out why one CEL stays on and the other goes out when started (for some reason there are two check engine lights)

Wow, how can they check and see it'* not the bulb yet you check and find paper towel stuck in there? That is infuriating.

You'll need to pull codes to see what you are starting with. Autozone as well as some other part chain stores will do this for free.

No kidding! Crazy the amount of effort some people will pursue to NOT just do something right the first time. Getting codes scanned and trouble shooting a few problems is not all that difficult these days.

breid what is the "text" of the two lights? You might have a Check Engine Soon and Service Engine Soon light. One of them (the SES) is just related to maintenance, and comes on for instance when the Oil Change "Remaining" indicator reaches a certain level like 10%. That has to be reset manually after the oil change is done, otherwise it just stays on. The engine doesn't know new oil is in there.

The top one is "service vehicle soon" bottom "service engine soon" They both come on for the initial system check but the bottom one stays on. Went thru inspection and they read P0420 sounds like the cat is bad but I was wondering if it could be the O2 sensors (probably original factory)

Okay, sorry I had my wording of the messages a little confused. Service Vehicle Soon is likely for the oil change monitor whenever it comes on, the other is for the stored error code that you determined.

What year and model Buick do you own? You should put this info in your signature(go to control panel to update your personal info).
As far as the P0420 code you probably have a bad catalytic converter. I had the same code with my 2001 LeSabre and my cat was fouled. You have to figure out what fouled it. In my case it was fouled by running rich and oil burning. You could get around the 420 code by installing an O2 eliminator(just GOOGLE it). I had to gut my cat because it had clogged. I never got anymore 420 codes since using the O2 "adapter".

Just a heads up...what Mad Coachman did, won't work in all states.....in some states, where you have emission testing of exhaust gases, a gutted cat will not pass the test...

I agree, MadCoachmen, don't offer illegal activities please.