I'm with the other two.. I would have just used the jumper wire method, and solved the whole problem. I wouldn't trust anything that said "temp. faker" on it. :-) Anyways, I just jumped mine awhile back, and said good bye to that problem of false readings.

I'm curious as to why, having already accessed the TCB, you didn't remove it and put in the jumper in its place.

The reason for asking is that the board does absolutely no good for you. It isn't just a question of being unreliable (especially given its age), but that it actually lies to you.

The board is there to dampen temperature swings -- actually, it was developed to stop the inquiries of american owners who are used to idiot lights instead of real temperature gauges, and who were unduly alarmed (and bothers dealers)when they saw the temperatures fluctuate normally (e.g., in traffic on hot summer days). Thus, the board keeps the gauge indicating exactly 9:00 until the temperature rises to a near critical temperatue, only then allowing the gauge to rise to near the read.
Thus, you don't get any early warning of impending problems (e.g., a leaky cooling system, etc.) -- with the board it is essentially just an "idiot gauge" (as in idiot light), where one moment is shows normal, and the next it's telling you that the car is already about to overheat.

So who would want to keep it that way, instead of (by simply bypassing the board) you will get a properly accurate and responsive gauge like any pre-'85 car?

Which is why I asked, having gone through the trouble of removing the instrument panel to access the board, why didn't you remove it instead of "fixing" and keeping it?

Best regards,