I have had the same problem for sometime and finally found my problem in a wire bundle that goes through the firewall on the drivers side ( the largest bundle) and the connection was #56 which had some rusting and I guess was not fully pushed in. Just like brand new now.
Most likely and bad blower motor resistor.
They come on when you turn on the windshield washer, but only when the headlights are turned on.
The radiator only, aprox 4 qts.
You need to replace the wiper motor.
Trying to find out if there is a high or low press. pump in the tank or if there is a pump on the frame rail. and wht the fuel press. should be? From 1992-1996 there are on a high pressure pump in the fuel tanks only..
I am wondering the same thing in 1994 safari van, have only wipers on high, i've unplugged the plug at the wiper motor & checked for power, only have power to wipers on high, now is the switch in the column with the signals,
The controller is bad Maybe, but wiper motors have high and low brushes. Check fuses, wiring, etc....
The resitor is probably burnt out on the high mode
The only other thing you can really do is get a manual from your local parts store or online. The cost is about $20.
possibly the multifunction switch is acting up or just bad
Blower Motor Resistor is bad. 20.00 part at AZ.
cause its a ford and there pieces of s**t