Hi,
I recently bought a 90 240 with what appeared to be a temperature compensation board problem. I replaced it with one that was working properly when I pulled it from another car. The temp gauge worked great for about 3 or 4 days. Now, when I start it up from cold, it doesn't seem to come up to temperature fast enough. The heater is blowing hot air and the gauge is still sitting at the bottom. After 15 minutes or so, the gauge comes to life and works perfectly. No random fluctuations like a "typical" temp comp board problem. My first thought is bad wire or connection somewhere but it seems like that wouldn't be quite so predictable. Or is this just a different manifestation of the temp gauge problem? Or bad sender? Any thoughts where to start?

Thanks!
Lyle