I have a 99 LHS and the other day I went to start it up and the gas gage was not working, the heater fan could not be turned down and the lights would not work. I drove it home and now it will not start at all. could someone please tell what may be the problem

 

Could be any number of things. The heater fan problem is probably a bad resistor but that would have nothing to do with not starting.

The place to begin is to check for codes stored in the computer. Try the "key dance" (key on-off-on-off-on) and see if anything comes up in the odometer space on the dash. If so, write down any codes that come up and look them up on the internet. You may need to get a code reader to read the codes.

Check the condition of the battery. A low battery will cause computer issues and will not be able to start the car.