Cruise Control, Horn and Airbag (SRS) Not Functional. Can't figure out issue. (1 Viewer)

[Chaldaean]

• Horn: Not responsive from the drivers seat, but I can jump the control relay in the engine bay and make it honk.
• Cruise Control: Nothing happens on the dash when I press the buttons.
• Airbag: Trouble light is illuminated on the dash (indicating a broken connection).

This sounded like a classic "clockspring" issue, so I replaced it with a new Toyota spiral cable (P/N 8430633020) and the issue still persists. I uninstalled/reinstalled multiple times to make sure.

I'm thinking that my next move it to completely remove the dash and look for a loose connector or damaged wire. Anyone know of a common cause for this? Is there a common harness buried somewhere?

 

[greentruck]

Haven't had my head under the dash in a year or so, so my memory on things is a bit hazy. But the EWD suggests maybe a bad ground. The simplest circuit is the horn and it shows a ground through the horn switch. This is suggested as part of the combinations switch, but that seemed wrong at first, they must mean the horn button? Or perhaps the wire is in the plug/circuit that also carries the combo sw, which makes sense. The plug diagram obviously serves that circuit, too. It's C14 and at the base of the steer column, looks like coming in from the driver's right foot side. If you ground pin 10 in it, it should honk. The ground is somewhere from the steer column to the chassis, which is where pin 10 goes after passing through the horn button.

The ground ID is in the left kick panel and all three of those circuits use it. The horn is probably safest to jump to it (careful with those airbags!) to see if that gets it to honk. It's the only one that goes through C14 and I'm guessing relatively easy to find in that dense wiring zone. It's black and has locations for 14 pins (although I don't think they're all used.)

Obviously, too, since you did the clockspring is to double check any other connectors you handled in that R&R to ensure they seated correctly or otherwise have no issues. There also the big copper ring that carries the horn circuit, which should be wired into the circuit that goes through C 14, pin 10 to ground. Not sure the other two circuits use it, but IIRC, it has a wire that connects from it to the harness and seems logical that it might be involved, even though no clear indication in the EWD (but It's late and I've been out painting a house all day.)