I have a 99 v6 accord that I put the engine out of a 01 in. I swapped ecu and wire harness. Everything works great except the temp gauge. I know the 99 has 1 sensor for the temp and the 01 has 2. But I am unsure of what to do to get the gauge working.
Any help is appreciated

 

I look at it the "other way". Meaning the 99 has two sensors. One for the PCM and one for the gauge unit.

The 01 has one - it feeds both the PCM and the gauge unit.

Now I can't remember if the gauge unit is different - meaning if the inputs from the PCM are different than the temp sender (98).

So with the newer PCM - Best I can tell C24 at the pcm is the signal for the gauge unit. In simple terms C24 from the PCM needs to feed C2 at the gauge connector.

Or do you put the temp sending unit for the gauge from the old engine on the new on - pretty sure the hole is still there and run a wire from the sender to C2 on the gauge connector.