volvo fuel gauge do not work
…and your question is…?
what is wrong with it
Electrons are cheap… you could be a little more descriptive if you tried.
Usually it’s the in-tank sensor when these do not work.
It’s broken.
If that’s your only problem, then you should feel lucky. 
BC.
If you want to fix it, figure $1,000+ dollars. That’s standard for a Volvo.
I had a non working fuel guage in a Volvo V70XC '98 and it was estimated at over $1,200 for a fix. That Volvo had two fuel tanks and a pump that moved gas from one tank to the other. God knows how the fuel guage sender worked.
I learned to use the trip meter and get gas every 300 mile around town and every 400 miles on an interstate trip. Never got it fixed.
Sorry, but if you have a Volvo you will have bigger problems than a fuel gauge.
Two possibilities:
- broken gage
- broken sender (see Oblivion’s post).
Alternative troubleshooting protocols
- check sender output
- check signal at gage
- test gage with simulated signal
Concur.