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busser
Active Member
29 Posts |
 Posted - 05/22/2019 : 3:48:13 PM
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| Hi. There are 5 buttons on my steering wheel: doors off/on, flashers, red, horn. However, there are only 3 wires leading away from the steering wheel. Could anyone explain? Thanks |
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Bluenozer
Top Member
Canada
644 Posts |
Posted - 05/23/2019 : 10:11:23 AM
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| clock spring connector under steering wheel is what all those go through |
OEM trained in wiring and all engine platforms for over 20 years
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exmod110
Senior Member
150 Posts |
Posted - 05/23/2019 : 12:58:55 PM
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| horn grounds in the wheel and is one wire through the clock spring. the switches all have different resisters on the other 2 wires. door open has no resister, close 1210 ohm, amber loading 6190 ohms and red over ride 2370 ohms. depending on the resistance on the circuit the bcm knows what button is being pressed. there also may be a wire for illumination if it has lit switches.. these values may change based on year and model. |
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WrenchMonkeyCSISD
Active Member
USA
30 Posts |
Posted - 05/29/2019 : 11:33:43 AM
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| Welcome to the wonderful world of multiplexing |
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busser
Active Member
29 Posts |
Posted - 05/29/2019 : 8:33:32 PM
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| Thank for the explanation. Where did you get your info from? In my opinion using the computer for simple on/off switches is a bad application of computerization. And it's not even digital. thanks again |
3005 IC bus CE300, DT466e engine, alison transmission, 206k miles |
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WrenchMonkeyCSISD
Active Member
USA
30 Posts |
Posted - 06/04/2019 : 09:22:28 AM
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| It's done because you can use a pair of twisted wire instead of multiple wires. Supposedly lowers cost, weight, and having to find paths for larger bundles of wires. |
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Topic |
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5 steering wheel buttons but only 3 wires out?
