Outside temp does not read new batterys in both inside & outside unit

I have had this Oregon Scientific model RAR186 unit for years and it works great. The only issue I ever have is when the batteries need to be changed in the remote sensor unit (Oregon scientific model #THN122). It never fails that once I change the batteries that the unit does not send a signal to the base unit. I will often hit the reset button and change the channels on the remote sensor before I finally remember that you need to do the following to get the sensor to talk to the RAR186 base unit: On the base unit (RAR186), hold down the CHANNEL and MEM buttons for at least two seconds. You will then see a graphic appear above the channel number that shows that it is searching for the sensor. Within a minute, you will then see the temperature displayed for the sensor showing that they are communicating. This is buried in the manual that you probably discarded as did I. Apparently, if your sensor is broken, you can either search to find a new sensor of the same model or also use the following sensors: THC138, THGR122NX, or THN132N I have not needed to replace the sensor as once I found the instructions to reset the communication between the sensor and base unit, all was fine. Hope this helps someone. I wrote this instruction using a Sharpie on the inside cover of the sensor since you have to remove 3 screws to replace the AAA batteries (2) in hopes I will remember next time and not waste my time searching the internet and not find the answer. Good luck! I have had this Oregon Scientific model RAR186 unit for years and it works great. The only issue I ever have is when the batteries need to be changed in the remote sensor unit (Oregon scientific model #THN122). It never fails that once I change the batteries that the unit does not send a signal to the base unit. I will often hit the reset button and change the channels on the remote sensor before I finally remember that you need to do the following to get the sensor to talk to the RAR186 base unit: On the base unit (RAR186), hold down the CHANNEL and MEM buttons for at least two seconds. You will then see a graphic appear above the channel number that shows that it is searching for the sensor. Within a minute, you will then see the temperature displayed for the sensor showing that they are communicating. This is buried in the manual that you probably discarded as did I. Apparently, if your sensor is broken, you can either search to find a new sensor of the same model or also use the following sensors: THC138, THGR122NX, or THN132N I have not needed to replace the sensor as once I found the instructions to reset the communication between the sensor and base unit, all was fine. Hope this helps someone. I wrote this instruction using a Sharpie on the inside cover of the sensor since you have to remove 3 screws to replace the AAA batteries (2) in hopes I will remember next time and not waste my time searching the internet and not find the answer. Good luck!