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| | | | Joined: Jan 2009 Posts: 246 Shop Shark | | Shop Shark Joined: Jan 2009 Posts: 246 | I have a 53 chevy truck just installed new wiring harness and applied power to it for the first time and I noticed when I turned the key on for a few seconds I noticed there was some smoke coming from ballast resistor does anyone know why ? | | | | | Joined: Feb 2004 Posts: 29,748 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,748 | That's not uncommon for a new resistor. Was the engine running at the time? If the points are closed with the switch on/engine off, the ignition circuit is flowing current all the time, and the resistor will get hot enough to burn someone if it's touched. That's why it's in a ceramic holder. Any dust or oil residue will burn off and smoke. If you need to have the switch on for an extended period of time without the engine running for some reason, disconnect the wire at the side of the distributor to protect the points and keep the resistor from getting hot. Newer solid-state ignition systems have built-in protection circuits to try to make them idiot-proof. When they built stovebolts and other oldtime vehicles, they assumed owners and mechanics had some common sense.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Jan 2009 Posts: 246 Shop Shark | | Shop Shark Joined: Jan 2009 Posts: 246 | No the engine was off . So it won't smoke while engine is running ? | | | | | Joined: Feb 2004 Posts: 29,748 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,748 | No, since the current switches on and off several times a second, the resistor doesn't have time to heat up. With the engine running at 2,000 RPM, for instance, the points open and close 10 times a second. Leaving the points closed for a minute with current flowing through the coil, the resistor, and the points overheats all those parts, and can burn the points, even with the resistor in place.
NEVER LEAVE THE IGNITION SWITCH ON FOR MORE THAN A FEW SECONDS WITHOUT STARTING THE ENGINE!
If you must leave the switch on for some reason, such as diagnosing a circuit problem, disconnect an ignition primary wire first, or put a piece of thin cardboard between the points to interrupt the ignition circuit.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Feb 2002 Posts: 12,029 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Feb 2002 Posts: 12,029 | a new ignition resistor will most always smoke when first used, once any contamination is burned off it won't happen again, but the resistor ceramic will always be hot while/after running, it's a heat sink on the dropping resistor, similar to the heater fan switch ... as said, with the engine not running it indicates the points were closed, now you know why they finally put an 'accessories' position on ignition switches  Bill | | | | | Joined: Jun 2012 Posts: 1,747 'Bolter | | 'Bolter Joined: Jun 2012 Posts: 1,747 | If you really want to run accessories in an AD truck, use a switch and run from the always hot on the ignition switch. How ever, if you don't turn it off when you park, you will have a dead battery. Only circuit I have contemplated doing this to my truck is the turn signal switch. Mine has a hazard flasher position that I might want to use with the truck off. Just a safety thing, my E brake is a little soft. New cables and adjusted but soft. I think the cables have some stretch in them. So if I stop to help some one I have to choose, let the truck run, lights flashing? Or truck off, no rolling.
Steve H
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