I'll apologize in advance if this has been answered previously, but a search didn't turn it up. I have some probably "dead" steering wheel audio switches on a 2006 Jaguar S-type, but would like to at least check any possible blown fuses, but the manual doesn't really do the trick in identifying just what that fuse might be? Anyone happen to know?

 

Does your cruise control work? Also, are you receiving any airbag codes? In my case, it was the clock spring. Symptoms were gradual. Audio controls went first, then a 1932 airbag code.

 

Cruise control works fine, no codes.

 

Certainly sounds like clock spring, stage 1.

Cheers,

Ken

 

Once the car is started the output at the battery should be more like 13.5 volts with alternator working. Shouldn't that be enough to adequately run the modules and electronics even if battery before start is 12.4 or lower?

 

No.

An alternator cannot supply the surges needed. People often think otherwise but there are dozens on here who've found it out and a new battery was the fix.

I say this regardless of whether the OP's problem is or is not battery related - I can't say.

 

+1. Only thing to add to [JagV8]'s comment is to forgive waning memory, coz last year's trawl thru old posts on this . . . numbered not "dozens" but many hundreds!

Perhaps you don't realize that the comms interrogation starts at "IGN ON" and that is before "START" drags the available battery voltage down into it's boots during cranking! If batt checks OK at >12.6V following o/night rest after full charge (before starting the car) then it's back to the next step of checking clock-spring.