Airbag Light Wiring

[R3N3]

Hi All,

I have replaced the factory dash with an IC7, however, for it to be road legal i still need to retain the airbag light.

I have purchased a standalone airbag light (as the Haltech doesn't have this capability..), which will be placed on the steering column (in a 3d printed housing). the question i have is in relation to the wiring.. i need to now emulate what the factory dash was doing. The factory wiring diagram is:

So, do i wire the positive side of the LED to pin 9 (+12v) and the negative side to both pin 22 (earth) and 3 (SRS ECU)?

Am i right in thinking i also need to connect pins 9&3 with some form of resistor?

I did electronics in school, but that was over 18yrs ago now.. so apologies if this is dead simple.

Edited June 21, 2023 by R3N3

[R3N3]

 

 

not sure why the image wasn’t showing up in the post above..

Edit - i have reinserted in this post, however the preview isnt working, click on it and it works

Edited June 21, 2023 by R3N3

[joshuaho96]

@R3N3 Not sure why I can't quote your post but I'm pretty sure the way it works is you need a resistor there to not have a dead short to ground if it grounds through the SRS ECU instead of the LED. That and you don't want to have the LED burn out from excessive current. The logic is probably that the SRS control unit needs to indicate at all times that the system is functioning to keep the malfunction light off. So presumably yes +12V needs to have a resistor in series with both the LED and SRS CU.

Keep in mind I'm a mediocre electrical engineer at best so take with appropriate skepticism. 

[R3N3]

@joshuaho96 I think there’s something funky going on with the forums..

thanks for your help. I got the old dash out and measured the resistance at 500ohms at the resistor. I’ll try put something together to simulate the dash.

[R3N3]

In case anyone wants to do this in the future, the wiring diagram is a little misleading. do not install the jumper cable between pin 3 and pin 22 shown in above posts. That just bypasses the light completely. Here is what i did:

The resistor was a 470ohm 1W resistor.