There isn't a control board - the controls are all in the switch.
The board is under the cap in the Wiper Motor.
if it is like my older model chev truck there is a circut board in the wiper motor assembly, (under the hood), that needs to be replaced. You can get the part at any auto supply store.
It can be either integral with the alternator or be part of the on-board computer.
usually in top right of fuse board
on the dash board
Trouble code P1870 means: Transaxle Component Slipping (4T60-E)
under the air vent next to the windshield on the outside of your car
Replace the paulse board that's attached to the wiper motor.
Fuel filter for 1995 Chevy Van is located underneath driver's side door at running board.
Left Front Speed Signal Missing - possibly ABS related - will research more
The fuel filter is located on the frame rail on the drivers side. It is an inline type, and may be either a threaded type of be held to the fuel line with clips.