The dash board light by speedometer only lights up on the side by the fuel gauge, so it's difficult to read the speed at night. How do I fix this?

Dash board ground behind the gauges would be my guess.

run fault codes and look for a speed sensor problem . If the speedo is not reading then any other items requiring a computation of speed/ distance will not work either.

there is a regulator for the display brightness, you may have it turn'd down or it has stopped working;. it controls the brightness at which the dash lights are. usually has a speedo sign on it. goes up and down. it works with the main light and is conecter to them on the same lighting board if it has gone then a new light swtch control switch will be needed.

check the printed circuit board on the dash panel

These lights for the dash are controlled by a rheostat instrument control dimmer switch next to the main light switch for the headlights, it is either turned off (have seen this dozens of times) or it is defective. Below is a picture of the switch assembly I speak of. The thumb wheel next to the knob is the dimmer control.

have you checked the fuses?

You need to check your main fuses under the hood first and then check them under the driver side dash board.

Blown Fuse or fried Circuit board. Take to a local AutoZone, Advance, Murray's, O'reillys or a similar part house for them to check the wiring. I'm assuming the van does not use a mechanical Speedometer or Fuel Gauge.

On the plus side, with no speedometer, your indicated odometer mileage does not increase. Just keep your speed down and your tank full. Kidding, just kidding.

remove dash and replace bulbs. if you are handy and remenber where the screws go you be ok

not sure but you have automatic lights the sensor is on dash on passenger side litttle black button looking thing. It might be covered.. if not just turn on your lights. the insterment dimmer is above radio too...