I have a 2001 Yukon. The battery is draining overnight now and I believe it is because after I take the keys out of ignition and shut the door the high beam indicator light and the cruise indicator light illuminates even though the lights are not on nor the cruise (approximately 10 seconds after the security light goes off those come on) no matter if I lock the truck or not. Several months ago I noticed this after having a new ABS system put in along with a new fuel pump...now the battery is draining overnight as a few months ago it would take several days. I did notice after replacing the ABS and fuel pump that the shift indicator lights (P RND34) and the speedometer would not work....but that hasn't happen in the last few months. Does anybody have any idea what this problem is? All is appreciated. Dusty
The first thing to do is to see if you can get the car checked out with a scanner, this is to see if there are any trouble codes stored in the computer memory.
If any codes are set then they should be repaired first before you go any further.
The next thing I would do is to check the charging system to see if the proper charging rate is being applied. A low voltage condition can play tricks on the computer system. If the charging system is at fault, then repair as required.
If nothing is detected then you need to find out where the draw is coming from. Disconnect the battery positive cable and install a test light in series, one end goes on the cable and the other on the battery terminal. If a draw is detected then the light will be illuminated bright. Then start disconnection fuses one at a time. When you find the circuit, the light will go dim or completely go out. Then you need to see what is in the circuit and inspect the wire harness connections at the components for loose connections, corrosion, or if the wire harness is shorted to ground by rubbing through somewhere and is touching any metal parts of the car.
Sometimes when you turn the key off and the lights on the dash light up, start moving the wire harnesses of the car under the hood, if you have a problem then wiggling the harness will make the light or lights go out or flicker. If you find and area that responds to the wiggle test, then inspect the area of the harness and connections for any faults listed above.
This is a start. Back track the mechanics work and find out what was installed. If modules or computers were replaced they should be inspected by a scanner to see if they were programmed properly. A module or computer not programmed properly can give false data putting the lights on at the improper times.
Check these things out. This is just a start. This could get complicated. We will be available for any further assistance you may need.
Let us know how you make out.