Sitting at a drive through, the temp light turns on very slow and dim. Let the car sit for 20 minutes checked the coolant reservoir the liquid is pink and at the right level between the min and max mark. Started the car no temp light, started driving again 2 miles into the drive and the light turns on again same way slow and dim and stays dim. As im driving the temp gauge starts going down to where the indicator is sitting between 1 and 8 and holding light still dim. Got home parked checked coolant level, the same as before. What would cause this?

 

Had the car checked out, the cooling system is working great. The temp light only comes on when i turn on the headlights, and 2 light bulbs inside the instrument cluster have gone out. The instrument cluster is on its way out. Do you guys know if the cluster can be fixed or just replaced?

 

There are two electrical components that can cause all kinds of seemingly unrelated electrical issues. One is the ignition switch (electrical portion, not the lock) and the other is the headlight switch. The ignition switch can be bought for around $30 (Audi part). The headlight switch is more but not prohibitive. I think they're worth investigating. To confirm that your coolant temps are good, just buy an inexpensive WiFi or Bluetooth ODB-II reader ($15-$30) to use with a smartphone and confirm the temps in realtime while you're driving.

The cluster bulbs can be replaced.

 

Thanks for getting back to me, I thought this thread was dead. The temp light comes on only when i turn the head lights on. The ignition switch has been changed 1 month ago. Good idea on the odb reader i will do that. I will also exchange the head light switch.