It's probably when it gets low - to warn you of freezing conditions.
Sounds like your coolant is low. check that the coolant level is right.
what are positioning lights on vw golf mk4
electronic stability program
98.6% F
Front side lights
To troubleshoot an engine management light on a VW Golf a diagnostic light is recommended. The test will display any malfunction codes it reads from the engine computer.
You can reset the brake warning lights, on your VW Jetta, by backing up 20 feet and using the brakes. The automobile will sense the new pads and the warning light will go off.
Yes, it is a Golf but VW stopped calling it the "VW Golf... GTI". Just as VW didn't call the R32 a Golf (although it is based on the VW Golf and has the same shape and many common components).
The temperature sender is probably grounded out and keeping it on.
In the thermostat housing
Add oil!
With a scan tool.
Yes the light bulb is replaceable.