Ambient temperature sensor

[Nick Jones]

One of the (many) issues I'm trying to sort is the ambient temperature sensor system. Though it seems trivial it seems to affect the way the climate control functions (ie no A/C). Anyway, it irks me to see it display 4ºC when it is >20ºC outside.....

Initially I inspected the G17 sensor behind the bumper and discovered the wires were damaged. I got another (C4 A6 one is the same). Plugged it in with a dash of contact cleaner and it worked....... for about 6 hours...... before returning to it's former ways.

I happened across a thread (http://www.audiworld.com/forums/a8-s...2806177/),that points out that it is also linked to a second sensor in the HVAC intake (G89?). I found this and tested it along with the G17 and found that both had the same resistance (approx 930 ohms @ 22ºC) with the resistance reducing if they are warmed. I think these are ok. Wiring plugs/contacts seem clean, no obvious damage and wiggling the wiring has no effect.

VAGCOM seems to show a sane reading from G89, but a low reading from G17 (though not as low as the dash display). I'm baffled now. Possibly there electronics in the dash insert are sick......

Any info on how these are wired would be much appreciated as having mended the A/C I'd really like to be able to use it!

Thanks

Nick