A few minutes after I turn the engine off on my 2003 envoy one of my tail lights comes on and stays on. what should I check? thanks

The tail light fuse is under the rear seat on the drivers side.

It could be your oil pressure sensor has gone bad.

you need to scan you vehicles ECM, there is a trouble code stored there. depending on where you live most parts stores( such as a shucks/orielleys) will have a scan tool they will let you use if the vehicle is in thier parking lot. this should diagnose the issue, provided the battery hasnt been disconnected since then.

Hello
Does the light ever come on while you are driving the vehicle? It is possible that the vehicle does not trigger the code on the key cycle when vehicle is connected to the OBDII scan tool (a cycle is the time from when a vehicle is started to the time the vehicle is turned off) you should however most of the time be able to check a vehicles trouble code history to see what may be turning the light on
Good luck
Chris

First and easiest we need to check for power going to the rear lights at the plug that goes into the tail light housing. There is a board that the lights plug into that goes bad. The Envoy uses separate brake and turn bulbs so the 3rd brake and the two side are on the same circuit.

There are a few things that you can do, do get it idling correctly, and it's fairly inexpensive.

1. Clean your throttle body with throttle body cleaner, with the battery disconnected. Needs to be shiny. When finished, drive around for 20 minutes or so with all accessories turned off, so the computer can relearn the newly cleaned TB. About $7 for the cleaner

2. Replace your spark plugs with A/C Delco 41-103, will idle better with this plug. Around $7 ea
3. Replace your upstream 02 sensor, the one right after the exhaust comes out of the engine, easy to replace. Between $67 and $80, try to stay away from Bosch.
4. Replace your fuel filter around $15 or less.
5. Check your vaccum lines for leaks.

Could be oxygen sensor in exhaust, if it gets a little too much rich exhaust it will come on intermittenly and go off when it dries out

Are you not getting a check engine light ? Take your suv to auto zone and get them to check it for codes and post the codes I will check back later to see what codes you posted they will help in finding the problem. Thank you

If you need further help, I’m available over the phone at https://www.6ya.com/expert/edward_020b3320326d263d

check globes and check brake light switch under dash on brake pedal.

This sounds like your alternator maybe going bad. When your alternator starts to go bad lights such as headlights, radio lights will go dim wipers will start to move slower but if you cut one of the things off such as the wipers the lights will get brighter for a few minutes then not long the car will shut completely down. Hope this helps.