What causes automatic climate control in a Daewoo Leganza 1999?

Answer 1

I hope this answer doesn't come too late, but this is a common fault on the Leganza. You need to replace the earth connection to the unit. It's quite easy to do, and doesn't need any specialist tools or knowledge. Remove the trim around the unit, unscrew it, and pull out. You need to identify the earth (thick black wire usually), and connect it to a good metal connection elsewhere. I ran mine to the negative pole of the cigarette lighter, and it's worked perfectly since. HTH.