my question to you
Because there is a known issue with the brake lamps on the 2003 Trailblazer. I own a 2003 Trailblazer and had to take it in for service on a recall due to the issue. Take it to your Chevy dealer and have them check the VIN to see if the recall was ever done.
6.5 litres
you will need to take the cover off the skidplate underneath with a regular screwdriver to access it
Take the gas tank down to get the pump out as it's inside the tank.
take off the battery pole and set it up again.
Dexron III Automatic Transmission Fluid
If it is a 4.2 v6 like mine, it will take 7 quarts of 5w 30 oil.
the orifice tube on a 2003 trailblazer is on the right hand side under the the air box Follow the high side line there is a 10mm nut you have to take off at a block {careful very fragile} the high side line is going to the evaporator from the condenser Dan
Most GM products, including the 2003 Trailblazer, take Dexron III transmission fluid. However, it is always a good idea to consult the owner or maintenance manual to be certain.
You take the screws out of the dash and remove the dash. Be careful or you will break it. After you get it off, you will have to disconnect like 3 wires to get it off, there are screws on the instrument cluster. You remove those and it pops right out. Mine went out in my trailblazer.
Take it to a local PepBoys they can scan if you have a check engine light on and from there I can help you more with diagnosing a misfire incase you have multiple problems
on the bottom toward the back of the oil pan there is oil sensor that may have gone bad. They must have not been that good since the 2004 don't have it. To get at it you must take the big plate down.