I must point out. Resistance does NOT cause heat. Current flow causes heat! If there is a heat problem in a conductor, that means there is more current flowing in that conductor than the conductor can carry without heating up. The misconception that resistance causes heat is a sure way to religate one's self to never being able to properly diagnose electrical problems. Why then does a corroded conductor often over heat? Different reasons. 1. If the conductor has corroded and is now smaller than it originally was, it will heat up. 2. If there is a build up of corrosion in an electrical connection, that corroded area will heat up when current flows through it. ...and others. What has to be remembered is, CURRENT FLOW CAUSES HEAT! That is a fact of physics and will never be proven wrong. ----- Original Message ----- From: "Neil Thorpe" <nt014b6628@xxxxxxxxxxxxxxxx> To: <mailing-list@xxxxxxxxxxxxxxxx> Sent: Monday, September 16, 2002 1:29 PM Subject: Re: IML: 81-83 headlamp switch and disapearing dash display I had tried to clean up the old light switch before ordering a replacement with electrical switch cleaner which didn't make any difference. The rheostat was corroded probably due to my car spending more time parked than driving 47000 miles in 20 years (ave 2350 miles per year) The corrosion had probably acted as an insulator instead of creating a high resistance therefore i have hopefully avoided the burnt wire problems you have encountered. One bonus of playing with the light switch so much is my fruit bat impression is getting much better. Neil Thorpe black 82 imp London, England.