I always thought it was the cable clipped to the side of the heater box but that video shows it under the carpet
Have I been using the wrong connector all the time?
If so, it will explain why I have never managed to get it to connect
In the video he is connecting to the engine ecu (which on his car is RH side of passenger footwell), the airbag ecu is the other side of the footwell by the heater box as you say.
If you cannot connect to your ecu try this chap from ebay -
I contacted him to confirm which cables I needed, these -
https://www.ebay.co.uk/itm/144489808013, then bought them from him
Crucially for me as my IT skills are limited, he offers tech support. He even offers remote access support. He logged into my laptop (numerous times), to help me get connected to the air bag ecu.
My big issue was I couldn't connect to the ecu, this ultimately was due to a USBC to USB adaptor blocking the signal.
I used my sons laptop with USB and we got it working.
I cannot praise this chap enough, it took a few days and in total a few hours to resolve all the issues and get the connection to work, the port setting etc, alone are minefield!
All for £17.99
