How do turn signals work?
Metzijndrie (Talk | contribs) (→The turn signal switch) |
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| − | Turn signals are one of the most misunderstood sub-systems in vehicles today. They really are simple when you stop and think about how the system performs its job, and why it is wired the way it is. Most commonly, the system is mis-wired and interacts with the brake lamp system causing non-functioning turn | + | Turn signals are one of the most misunderstood sub-systems in vehicles today. They really are simple when you stop and think about how the system performs its job, and why it is wired the way it is. Most commonly, the system is mis-wired and interacts with the brake lamp system causing non-functioning [[turn signal]]s under braking conditions, and 4-way flashing action when not in braking mode. |
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==Power feed and flash unit== | ==Power feed and flash unit== | ||
| − | Power on a traditional flash unit is delivered to the system via the flash unit. A fused, switched lead is run from the fuse buss to the flasher, so that it only receives power in the "Hot in Run" position. | + | Power on a traditional [[flash unit]] is delivered to the system via the flash unit. A fused, switched lead is run from the fuse buss to the flasher, so that it only receives power in the "Hot in Run" position. |
From the flasher, a wire is run to the center wiper (or moveable contact) of the turn signal switch inside the steering column. | From the flasher, a wire is run to the center wiper (or moveable contact) of the turn signal switch inside the steering column. | ||
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The switch itself, located below the horn ring on most traditional systems, is like any other, except that it is two switches in one, the left side and the right side. It also provides the isolation required between the brake lamp system and the turn signal system. | The switch itself, located below the horn ring on most traditional systems, is like any other, except that it is two switches in one, the left side and the right side. It also provides the isolation required between the brake lamp system and the turn signal system. | ||
| − | To understand how the switch works, we can view one side of it as an example. If you remove the steering wheel (and usually the horn assembly), you can see the turn signal switches. They are usually on a plastic base plate, driven by a plastic cam, and set off by two spring steel contacts that shift contact points when the base plate is activated with the turn signal arm. | + | To understand how the switch works, we can view one side of it as an example. If you remove the steering wheel (and usually the [[horn assembly]]), you can see the turn signal switches. They are usually on a plastic base plate, driven by a plastic cam, and set off by two spring steel contacts that shift contact points when the base plate is activated with the turn signal arm. |
[[Image:Puller_steering_wheel.JPG]] | [[Image:Puller_steering_wheel.JPG]] | ||
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*The center wiper (moveable contact or cam contact) is lamp output. | *The center wiper (moveable contact or cam contact) is lamp output. | ||
| − | *The normally closed contact is brake lamp power from the brake lamp switch. | + | *The normally closed contact is brake lamp power from the [[brake lamp switch]]. |
*The normally open contact is power from the flash unit. | *The normally open contact is power from the flash unit. | ||
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Tools and materials needed: | Tools and materials needed: | ||
| − | *Digital Volt-Ohm Meter | + | *[[Digital Volt-Ohm Meter]] |
| − | *Jumper wire set | + | *[[Jumper wire set]] |
*An accurate diagram | *An accurate diagram | ||
*Contact cleaner | *Contact cleaner | ||
*Acid brush | *Acid brush | ||
| − | *Standard hand tools | + | *[[Standard hand tools]] |
*Dental pick | *Dental pick | ||
*Emery cloth | *Emery cloth | ||
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