02 to 99 3.8L Swap

I dropped an '02 3.8L and tranny into a '99 (was also a 3.8L). I noticed a couple of small differences on the wiring so I also used the '02 wiring harness.

The motor fired right up but I have a few small issues:
1. The cooling fan immediatley comes on and stays on
2. The temperature guage does not work (worked before)
3. The A/C will not engage (worked before)

I'm not quite sure where to start looking. I'm hoping that it's something fairly simple. Any suggestions are appreciated.

Yes, the biggest reason that I used the 02 harness was because of the temp sending unit. It's on the back-side of the head on the 02 and it's near the water pump neck on the 99.

Yesterday, I grabbed my multi-meter and started chasing wires.

On the 99 harness, I found the temp sensor on Pin 16 of the 42-pin connector. On the 02, I found it on Pin 5. I pulled it from Pin 5 and moved it to Pin 16 (which was empty on the 02 harness).

Now when I fire up the motor, everything appears to work fine. The cooling fan doesn't immediately start running, the AC works, and the Temp guage appears to be working.

So do I need to switch the 02 motor from CHT to ECT or will the 99 electrical system be able to handle it?

I haven't hooked up the oxygen sensors yet. I think that I will need to move another pin for those to work properly.

Thanks for the reply.