My oil level, coolant level, brake warning a charging system warning light stay on continuously though there is nothing wrong with them. Consequently, my electrical system drains while driving. What's causing this?

 

You do know the section of the forum you're posting in supports 3 generations of LS400 spanning 10 years right? Some info would be handy.

Your electrical system shouldn't be draining while you're driving. Get your alternator checked.

 

The Volkswaggon people post here all the time.

 

Most likely the alternator. Get this checked ASAP or you may also be looking at a new battery after a very deep discharge.

 

Could be a host of things as you've neglected to list the year of your Stanley Steamer.

As mentioned I would look at the alternator, battery charge and terminals, and if both of those are good and you have an 89-94, the trunk hinge harness. Fix for that is here: http://www.lexls.com/tutorials/lighting/bulbout.html