New 2g owner with temp gauge problem

[Coach Moe]

Hey y'all. I am a new owner of a '97 spyder 2.4. 117,000 miles. I just replaced the alternator and all is functioning as it should EXCEPT the temp gauge and fans. I've checked and re-checked to make sure all connections are in place. Only 3 of which I disconnected in the install....hot, ground, and electrical connector (all on alternator). After "test" driving for 10 minutes the temp gauge never showed current temp as it stayed below the cold mark. I parked it, popped the hood and neither fan was engaged either. Any ideas? Any input or advice would be greatly appreciated. Thank you.


EDIT.....After further research, I found that the electric fans engage when the optimal temperature of the coolant is reached. Correct? If so, then that problem is solved. As far as the temp gauge not working, where do I need to begin with diagnosing that problem? Thank you.

 

[PlanZero]

There's two sensors on the thermostat housing. The bigger one is the coolant temp sensor and the smaller one is the temp gauge sending unit. The smaller one is the one you may have to replace. Try unplugging it, cleaning it with a little alcohol on a qtip and plug it back in. Mine worked fine after that.
Also, only one of the fans actually kicks on low or high depending on the temp. the other fan is for your ac, and automatically goes on when you hit the ac button.

 

[luv2rallye]

After further research, I found that the electric fans engage when the optimal temperature of the coolant is reached. Correct? If so, then that problem is solved. As far as the temp gauge not working, where do I need to begin with diagnosing that problem? Thank you.

Yes that is correct. As for the temp gauge, ground the harness wire on that single wire temp gauge sender (temp gauge sending unit). When turning the key to on, the dash temp gauge should slowly go to full hot. If it does then that sender is bad. If not you have a wiring problem.

 

[Coach Moe]

I appreciate the replies. That helps tremendously, and that is where I'll begin with attempting to repair the problem. Thanks again.

 

[Coach Moe]

As you thought, it was the sending unit. Replaced today and now works as it should. Can't thank y'all enough for your advice and knowledge. EASY FIX, once diagnosed.