

| Subject: | Re: headlight problem and "bad "grounds. SVX |
| From: | David Beierl |
| Date: | Thu, 5 Jul 2001 17:05:16 -0400 |
At 03:25 PM 8/5/2001, pensioner wrote: >Bad grounds.. contrary to info presented on the list. A bad ground will not >cause a switch to overheat. Overheating switches are caused by contact >resistance at the high current contacts in the switch. The dimmer Right (as you know). To amplify a little, the total power dissipated in a circuit gets distributed proportionally to the resistances in the circuit. In a headlight circuit you ideally want zero resistance everywhere except the headlight filament, in which case all the power would go there. In an actual circuit you have resistance in the wires, the crimps, the push-on terminals, the switch contacts, all of which dissipate power, i.e. heat up. A higher-than-normal resistance anywhere along the circuit will cause that part to heat up more than expected. This causes things to melt, and makes the headlights soggy and hard to light. As the rogue resistance goes up and up and up, the total power dissipated in the circuit goes down, so eventually you reach a point where nothing overheats (but the lights don't light either). david David Beierl - Providence, RI http://pws.prserv.net/synergy/Vanagon/ '84 Westy "Dutiful Passage" '85 GL "Poor Relation"
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