2006 Citroen Xsara Picasso 1.6 petrol

[WoodySenior_2019]

A couple of, hopefully, easy questions that I need an answer to.
Having managed to change the battery, which is under the driver's seat in a French LHD model, which I have living in France, and only achieved

The black flexi tube on the left of the battery.

after buying a number 40 Torx screwdriver bit!
This was required to remove the three screws holding the seat down so as to be able to swing the seat up out of the way. NB no easy clips as shown on most YouTube Videos for RHD models where the battery is mounted under the passenger seat.
The old battery had a plastic pipe fitted to the vent on the left-hand side of the old battery looking from the rear.
The new battery vent on the left-hand side has the black fixed plug in it and the yellow removable one is on the right-hand side.
Now the first question: Do I need to extend the plastic tube somehow and push it into the vacated yellow plug hole or is it OK not to bother?
My worry is if the acid or the acid fumes pass into the car as opposed to an under bonnet 'normal' battery position where it would vent to the open air.
Now my second question: The air temperature gauge has never worked. It changes back and forward between 0°c and 0°f with no trouble but no reading of the actual temperature appears.
Any ideas on how to find the fault and rectify it would be welcome.
Thank you in anticipation.

[GiveMeABreak]

You must vent cabin-located batteries! So yes either get the correct battery type or do a mod, but you must vent it.

As for the outside temperature sensor - I'm assuming you are referring to the 'nipple' located in one of your rear view mirrors. These can fail if they've been knocked or just generally wear out. They are cheap enough to get hold of, but you've got to disassemble the mirror to get the old sensor out and replace - along with potentially some of the door trim...

First thing I would do though is check for wire breaks in the loom from the door to the bulkhead. Inside the rubber loom protection sleeve is the usual place where these can wear and break through opening and closing the doors over time.

[wheeler]

after buying a number 40 Torx screwdriver bit!
This was required to remove the three screws holding the seat down so as to be able to swing the seat up out of the way.

Not sure if your aware & its just missing but the torx key needed to undo the seat bolts should be clipped to the underside of the lid of one of the compartments in the rear floor.

[old-un77]

so, having purchased an 56 Desire last February, with around 25,000 miles on the clock (verified by mot records,)and in this covid year have added around 4500, due to its lack of use, the battery is not holding its own, recalling my earlier 1.8 pic's battery being under the passenger seat , accessed by flipping two catches, and tipping the seat forward, was a bit put out by not (apparently) being able to access the battery easily....had to re ignite my membership of of this forum....with great success....the torx wrench was indeed still under the left footwell cover....pity it isn't double ended!!!

thanks for the info!!
Bob (now 83...)