06 volvo s40 while driving down the road windshield wipers went on and off the low brake fluid message came across. pulled over turned off car could not get key out tried to restart nothing happens. disconnected battery and was able to get ket in and out still nothing happens when I turn the key. replaced battery and still same thing nothing happens. I can hear the fuel pump working

SOURCE: VOLVO S40 2001 HEADLIGHT WIPER MOTORS

you can disconnect the wiper motor from the harness by just removing the plugs don't have to worry about a fuse.

SOURCE: 2000 volvo s40 cannot remove ignition key

The swich that you press when you want to change the gear mode("p" to "d" ) remain jam very coomon for an s40 spary silicone spary on it to remove dirt from there

SOURCE: how do i gain access to fuelpump on 2002 volvo v70

From Volvo Cars of North America letter I received:  "[Volvo] has voluntarily decided to extend warranty coverage for the fuel pump on U.S. model year 2001-2002 Volvo S80, S60, V70, and XC70 vehicles."
The letter goes on to describe conditions that in the end, may result in a fuel odor.  "Coverage is limited to the symptoms described in this letter for the fuel pump only." 
Contact a Volvo dealer to have this corrected under warranty.  If you already paid to have this fixed, then you can submit the repair order with a copy of the warranty letter (keeping both for your records) to Volvo on the address on the letter.  If you did not get the letter, I'd suggest contacting Volvo.
Bottom line is that you should not have to pay to have this fixed.

SOURCE: Rear windshield wiper sprayer

it might be in the motor pump or line is clog can you work the hose

SOURCE: My Volvo 960 stalls while driving

It could be a number of things. Fuel Flow problem, or electrical apparatus heats up and works inefficiently. You could start from the cheaper, less strainous solutions, in this order: Change Fuel Filter, and clean Nozzles. Fuel Pump, Air Mass Meter.