After re-fitting my instrument cluster in the Mk2 today (new speedo following the old one becoming very inaccurate), I noticed that the coolant temperature gauge wasn't indicating the temperature, despite the car running for around 15-20 mins. When I turn the key, the little red light above the temperature gauge flashes as per normal, but the gauge doesn't register any temperature as the water gets hotter! I'm trying to trace the fault right now... The connector block that connects to the instrument cluster is a little chewed up as it has been removed and re-inserted hundreds of times, but I'm fairly sure all of the connectors are making contact (I believe the ones for the coolant temp gauge is a blue and yellow one and this one is in perfect condition). Every other part of the instrument cluster is working perfectly. I have also tried swapping it with another instrument cluster to rule out a faulty gauge, which leaves either the wiring to the instrument cluster faulty or the temperature sensor faulty.
My questions are:
1. When the red light next to the coolant gauge flashes, does that mean that the gauge is also receiving a signal?
2. Is the coolant warning light a separate thing to the gauge, or do they work together?
3. Assuming the gauge doesn't work, would the light still flash if the coolant got a little too hot?
4. I tried plugging the wire for the black temp sensor into the blue temp sensor to see if I could get the gauge to read this way, but it still didn't read anything. Would the blue temp sensor send a signal that would be compatible with the coolant tempt sensor?
It's quite important to me that this works as it can run a little hot at times (when driving slowly), so I like to keep an eye on it!
Thanks in advance for any help!
