Would you please tell me where each temperature sensor is and which is which? THX!

Thanks...this makes perfect sense...I have a viscous coupling and the radiator does look recent. OK...so the temperature gage is not working. What is the most common reason for that and would you expect it to affect the engine control unit logic and/or cold starts?

I recently purchased this car here in Phoenix but will be leaving it in a cold winter climate. Although it runs well in Phoenix, naturally I am concerned about cold weather starting. The temperature gage does not work and I notice that there is a coolant temperature senser in the radiator without a ...