Instructions manual for La Crosse WS-9035TWC-2S

You likely need a new one as factory reset is done via the Set Button..

La-Crosse Support

https://www.lacrossetechnology.com/products/ws-8248

https://lacrossetechnology.zendesk.com/hc/en-us/articles/5278162570395-Atomic-Clock-Factory-Reset

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https://www.manualslib.com/manual/1023320/La-Crosse-Ws-9160u-It.html?page=2#manual

Question edited for clarity. Full 'make model (what it is)'.

Did you put batteries in both units and in the right order, sensor first?

Step 1: Insert 2 fresh AA, batteries into the TX29U-IT sensor according to the polarity marked in the battery compartment.

Step 2: Insert 2 fresh AAA, Alkaline batteries into the wireless thermometer according to the polarity markings. Step 3: After 5 minutes place sensor outside in a shaded location.

https://www.lacrossetechnology.com/products/WS-9160U-IT#support

Retired unit so no further warranty or parts.

You can still get one on Amazon

La Crosse Technology WS-9160U-IT Digital Thermometer ...

Amazon.ca https://www.amazon.ca > Technology-WS-9160U-Digita...

Digital thermometer with wireless remote and clock; Remote sensor transmits from up to 330 feet; records daily high and low temperatures; Receives weather ...
Rating: 4.4 · ‎ 7,970 reviews · ‎ $31.50 · ‎ In stock
..

https://www.lacrossetechnology.com/media/catalog/product/w/s/ws-7014u-it.pdf

https://www.manualslib.com/manual/91066/La-Crosse-Technology-Ws-7014u.html

https://www.manualslib.com/manual/516326/La-Crosse-Ws-7014ch-It.html

Slightly different names models, but free manuals.

https://www.manualslib.com/manual/91064/La-Crosse-Technology-Ws-1612.html

http://www.manualslib.com/products/La-Crosse-Ws-8256u-2940322.html

Hi Vickie....try this....good luck to you.
Regards,
Dennis

WS 8418AL IT Tomorrow Weather Today by La Crosse Technology

The WS-7395U uses the La Crosse TX8U outdoor temperature and humidity sensor. That part has a $49.99 MSRP. It is $46.95 from La Crosse; see http://www.lacrossetechnology.com/tx8/index.php to order the part. Other vendors that I checked do not have the sensor in stock for sale separately.

I hope this helps.

Cindy Wells

Solved it! La Crosse let you download manuals from their website.