Originally Posted by derf

There must be a communications module in the dash/cluster that talks to the body control module which is where most of the stuff on the interior of the car is centrally controlled. Similarly, there is a communications module in the transmission, one for the engine, another for the HVAC, and so on and so on. When one of those modules stops communicating, It doesn't receive signals that are being sent out to it to do things like turn on the cluster lights, turn off the headlights etc.

The fact that the cluster lights come on when you take the key out makes it sound like the ignition module is somehow involved. Or should I say that detection of the key being present is involved. What sucks is that you cannot read the codes with the key out unless you can find a way to put the car in run without using the key which I don't recommend unless you truly know what you're doing. Even if you subdied 12 volts to your OBD II MX+, I don't think anything else would have the power to have the computer awake for you to read the codes.

To be clear, after you remove the key, does the headlight switch work properly for example? Or the dimmer switch when the dash lights are on with the key out?

Unfortunately we don't have an Astra specialist right now. Actually not ever but we will try to help you solve your issue cuz that's just what we do on this forum. Have you looked for TSBs on your vehicle? Also, how soon did this show up after you purchased the vehicle? Communications failures generally do not just suddenly occur. Meaning to previous owner May have known but cleared the codes before you test drive it, etc.

Originally Posted by derf

There must be a communications module in the dash/cluster that talks to the body control module which is where most of the stuff on the interior of the car is centrally controlled. Similarly, there is a communications module in the transmission, one for the engine, another for the HVAC, and so on and so on. When one of those modules stops communicating, It doesn't receive signals that are being sent out to it to do things like turn on the cluster lights, turn off the headlights etc.

The fact that the cluster lights come on when you take the key out makes it sound like the ignition module is somehow involved. Or should I say that detection of the key being present is involved. What sucks is that you cannot read the codes with the key out unless you can find a way to put the car in run without using the key which I don't recommend unless you truly know what you're doing. Even if you subdied 12 volts to your OBD II MX+, I don't think anything else would have the power to have the computer awake for you to read the codes.

To be clear, after you remove the key, does the headlight switch work properly for example? Or the dimmer switch when the dash lights are on with the key out?

Unfortunately we don't have an Astra specialist right now. Actually not ever but we will try to help you solve your issue cuz that's just what we do on this forum. Have you looked for TSBs on your vehicle? Also, how soon did this show up after you purchased the vehicle? Communications failures generally do not just suddenly occur. Meaning to previous owner May have known but cleared the codes before you test drive it, etc.

Originally Posted by 02 LW300

Sounds like the start of body control module problems to me. However I have L series cars not Astras. Both are European design though.