Steering wheel swap - where to route the horn...

[DenverAirport]

I'm attempting to swap steering wheels from my OE to a Celica wheel I bought on eBay.

I'm hoping to reuse the 4runner cruise control if possible as I didn't get a cruise control lever with the Celica wheel.

While the switch itself looks like it will be able to mount onto the wheel without a problem, one wire (what I believe is the horn) does not have a place. I'm wondering if there is any place I can attach it on the Celica wheel and keep its functionality?

 

[sleepydad]

I'm attempting to swap steering wheels from my OE to a Celica wheel I bought on eBay.

I'm hoping to reuse the 4runner cruise control if possible as I didn't get a cruise control lever with the Celica wheel.

While the switch itself looks like it will be able to mount onto the wheel without a problem, one wire (what I believe is the horn) does not have a place. I'm wondering if there is any place I can attach it on the Celica wheel and keep its functionality?

in theory as long as you can bring over all the electrical connections from the 4runner wheel to the celica wheel and re-use the old clock spring it should all just work. you will have to splice in the celica wire for the horn where-ever the 4runner horn was connected. I would guess it's just one wire acting as an open ground? I would have to dig into the wire diagrams to know for sure but pretty sure it's just one wire.

so the loss of the airbag does not bother you?

 

[DenverAirport]

in theory as long as you can bring over all the electrical connections from the 4runner wheel to the celica wheel and re-use the old clock spring it should all just work. you will have to splice in the celica wire for the horn where-ever the 4runner horn was connected. I would guess it's just one wire acting as an open ground? I would have to dig into the wire diagrams to know for sure but pretty sure it's just one wire.

so the loss of the airbag does not bother you?

I’ll try to find a pic because I don’t have the Celica wiring but it looks like there’s usually an open ground wire on the that is attached to a small metal piece on the upper right side of the wheel. Seems like this could be the horn. I guess I’m struggling a bit to understand how the horn works if it’s just an open ground wire. I know if the contacts are made between the airbag cover and the metal inside that triggers the horn but does the wire just sit and act like a ground in this process?

In terms of airbag I have a celica airbag and it fits my original clock spring!

 

[sleepydad]

I’ll try to find a pic because I don’t have the Celica wiring but it looks like there’s usually an open ground wire on the that is attached to a small metal piece on the upper right side of the wheel. Seems like this could be the horn. I guess I’m struggling a bit to understand how the horn works if it’s just an open ground wire. I know if the contacts are made between the airbag cover and the metal inside that triggers the horn but does the wire just sit and act like a ground in this process?

In terms of airbag I have a celica airbag and it fits my original clock spring!

it's just a momentary contact switch, there must be a hot/ground pare for the air bag, then a dedicated ground for the horn. so 3 wires going into the airbag part, 2 wires for the bag, 1 wire for the horn. when you then press the big airbag button it makes contact and returns the ground on the 1 wire coming out. trips relay and the anemic sounding beep happens.

 

[phattyduck]

I guess I’m struggling a bit to understand how the horn works if it’s just an open ground wire.

Generally:

12V --> Fuse --> (Horn Relay or Horn) --> wire to horn button --> momentary switch (horn 'button') --> ground through steering wheel/column.

The ground connection goes through the steering wheel frame to the steering shaft. The open connection (when horn is not on!) is between the airbag frame and the main steering wheel frame. If you look on the 4Runner airbag mount, you'll see special contacts between it and the steering wheel frame where the actual 'switching' for the horn happens.

You need to figure out how the Celica horn is triggered in/around its airbag frame assembly and attach the red wire to the ungrounded side of that.

-Charlie

 

[DenverAirport]

Generally:

12V --> Fuse --> (Horn Relay or Horn) --> wire to horn button --> momentary switch (horn 'button') --> ground through steering wheel/column.

The ground connection goes through the steering wheel frame to the steering shaft. The open connection (when horn is not on!) is between the airbag frame and the main steering wheel frame. If you look on the 4Runner airbag mount, you'll see special contacts between it and the steering wheel frame where the actual 'switching' for the horn happens.

You need to figure out how the Celica horn is triggered in/around its airbag frame assembly and attach the red wire to the ungrounded side of that.

-Charlie

This is super helpful! Thank you man. After playing around with this I also think in order to make this connection properly I'm going to have to get a different sized cruise control switch. Will update as soon as I test this out!