We have 2006 jayco Poptop. Our problem is these a hose for the water tank what's the other hose for please

Not much on it. Contact Jayco direct in the morning.

https://www.google.com/search?q=2014+jayco+pinnacle+36kpts+water+diagram

..

Question edited for clarity.
Question moved from Cars and Trucks.

2003 Jayco Designer Pump location? - Jayco RV Owners Forum

https://www.jaycoowners.com > forums > 2003-jayco-d...
Jun 21, 2020 - The water pump is accessed from the bottom rear of the Designer. Remove the ABS belly pan and there is the pump. Be prepared to have a helper.
Designer Water Pump Strainer
Sep 22, 2017
Water Pump Location
May 9, 2016
water pump
Sep 16, 2013
Water pump location?
Oct 10, 2018
More results from www.jaycoowners.com

There may be a solenoid that opens like on a washing machine to divert water to the fresh water tank.

And it appears there is

https://www.google.com/search?q=jayco+34rsbs+fresh+water+inlet+manifold

..

Look underneath the camper for a drain valve. Never seen a Jayco without a factory installed drain valve.

Disconnect clear water supply/hose. Turn on 12v pump. Turn on the sink faucets and open the grey water drain. Wait until the faucets start spitting water (you'll know).
Complete.
If you wish to split hairs yes there will be residual water left somewhat in the system but the tank will be emptied. Good luck and happy camping

Need a new valve!

If you fill the tank completely when the water vents you'll see were it comes out . Usually a hose from top of tank going down the side of tank then through floor and will have a screen on end to keep the bugs out.

if you are talking about a hot water tank or gas fridge,it needs a thermos coupler

Contact your local service center directly or online here