School Bus Fleet Magazine Forums
Home | Profile | Register | Active Topics | Members | Search | FAQ
 All Forums
 Professional Garage
 Enter Forum: Professional Garage
 5 steering wheel buttons but only 3 wires out?
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

busser
Active Member

26 Posts

Posted - 05/22/2019 :  3:48:13 PM  Show Profile  Reply with Quote
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

Bluenozer
Senior Member

Canada
178 Posts

Posted - 05/23/2019 :  10:11:23 AM  Show Profile  Reply with Quote
clock spring connector under steering wheel is what all those go through

OEM trained in wiring and all engine platforms for 20 years
Go to Top of Page

exmod110
Senior Member

115 Posts

Posted - 05/23/2019 :  12:58:55 PM  Show Profile  Visit exmod110's Homepage  Reply with Quote
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.
Go to Top of Page

WrenchMonkeyCSISD
Active Member

USA
23 Posts

Posted - 05/29/2019 :  11:33:43 AM  Show Profile  Reply with Quote
Welcome to the wonderful world of multiplexing
Go to Top of Page

busser
Active Member

26 Posts

Posted - 05/29/2019 :  8:33:32 PM  Show Profile  Reply with Quote
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
Go to Top of Page

WrenchMonkeyCSISD
Active Member

USA
23 Posts

Posted - 06/04/2019 :  09:22:28 AM  Show Profile  Reply with Quote
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.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
 


School Bus Fleet Magazine Forums © 2017 School Bus Fleet Magazine Go To Top Of Page
This page was generated in 0.08 seconds. Snitz Forums 2000