I'm trying to figure out what the ignition wire is on the back to of the push to start (SCU) on a 2007 S80 3.2

There are four wires

Red - constant voltage
Black - ground
Gray- ??
Blue/White - ??

 

Lets see if this screen capture works - I'll give it a try

Tim

 

Hi Tim

Thank you for your response, however, I have the same diagram from
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page 62 - however it doesn't specify which is the ignition wire that stays hot when the engine is started - I put a volt meter on put the Blue/white to on and the blue does give some voltage and I didn't get one from the gray - but the the engine starts it appears that the voltage drops from the blue/white

 

now your above my pay scale

 

What are you trying to do? Those wires are the input signal from the start button and the LIN communication wire.

 

Are either of the two a typically ignition eire thst stsys hit while the motor is running?

 

Nope.

 

So whats the best location to find a constant hot - red - and the ignition wire that stays hot while the motor is running?

 

What are you trying to do?