Windshield wipers

Since you are up at the control switch already, check for twelve volts on the dark blue wire with the ignition switch on. If that is missing, check if the rear washer works. If that is dead too, the suspect is a defective semiconductor circuit protector, which I have never heard of, or that circuit has a short to ground on it. The front washer motor is on that circuit too.

Tell me what you find, then I will figure out where to go next.

The dark blue wire is the 12 volt feed for the front washer motor. We know that's good cuz it works. That's the same 12 volt feed for the wiper switch.

I should have mentioned before, ... The first thing to always check is grab a test light and ground it to anything other than the plate the wiper motor is mounted on, turn the switch to "low" or "high", with the ignition switch on, then probe the case of the motor. If you see any voltage there, the brass ground strap is arced away under the mounting bolt. Attaching a new ground wire will solve that.

You have the right wires but in reverse order from the diagram. Wire number 1 is brown / white. That is for low speed. Number 3 is high speed. That's the red / yellow. If neither of those has 12 volts, look at the "Wiper on" relay. Wire 2 is dark green / white. That is for the internal switch that grounds a terminal on the Body Computer when in the "park" position. When you turn the wiper switch off, or when in "delay" mode, and the wiper arms reach the "park" position, the Body Computer switches the "Wiper on" relay from supplying 12 volts to supplying a ground. That shorts out the spinning motor which puts a heavy load on it to force it to stop rather than keep on coasting. It would coast far enough to turn the "park" switch back off, and the wipers would keep on running unless you held the arms down by hand. (A spinning motor acts like a generator. That's why shorting the wires makes it stop almost instantly).

Wire 4 is black and is the ground wire. It appears that takes the place of that brass ground strap I mentioned.

Check fuse 19, a 30-amp under the hood. If that's a spade-type fuse, it will have two test points on top. There should be 12 volts on them all the time. Next, go to the wiper switch and check for 12 volts on the dark blue wire. The ignition switch has to be on for that one. If you have that, go to the dark green / yellow wire. You should see a real low voltage there when in the "off position, and it should go higher and higher as you turn the switch toward "high".

If you have that, the most common suspect is the Body Computer. To verify that, lift the "Wiper on" relay just enough that you can probe terminal 85. The relay has to be plugged in for this test. If you can't get a probe in there, remove the relay, then stick a piece of wire into the terminal, then install the relay over it. That wire will provide the test point. Be careful to use a small wire so it doesn't spread the terminal in the fuse box and create a future intermittent problem. You will see 12 volts there when the wipers are off. If you don't know how to tell 85 from 86, remove the relay, then measure the voltage on those two terminals. Terminal 86 will have the 12 volts on it. You want 85, the one across from 86.

Back to 85 with the relay installed. If you see 12 volts there when the wiper switch is turned on to "low" or "high", the Body Computer is not grounding it and is the suspect. To verify everything else is okay, the wipers should run when you use a jumper wire to ground your test wire / 85.

I had another one about ten years ago that the owner wired in a toggle switch. Just another case of the insane engineers adding an unnecessary computer to a circuit that never needed one before. They found a solution where there was no problem.