4WD, ESP and anti slip lights are glowing

Hi,

I had my Nissan XTrail 2011 at the local brand mechanics today due to 4wd,
esp and anti slip lights glowing. They have been glowing for about 7 months
now so I figured it was about time to do something about it. I got a call from
them and it turns out I have to change the 4wd control unit (among a few
other things that they mean aren't related to this), one of the things is that the
battery should be changed.

What bothers me though is that the same place said that it was the 4wd
"vent" 7 months ago after doing the diagnostics , which had a tag around
500£. But this time it was the control unit that cost around 5900£. All in all it
would cost me 8900£ fixing all the things (rear wheel brakes, changing the
4wd control unit, switching battery, changing some light bulbs to mention the
biggest things) so I was hoping that I could do some diagnostics myself in
terms of the 4wd thingy.

I've read that the lights can start to glow due to light bulbs on the exterior, for
instance?

Note: The 4wd and esp are turned off and in the beginning the lights started
glowing, then stopped glowing after i turned my car off and on, after a few
days they started to glow again until they started glowing constantly. The
model is named x-trail in Norway, I'm not really sure what the model name is
here though.