inline pigtailed diode from wipersin my 72 E200 is burnt out and it was why my wipers quit in low and would not go into park .why is is it there??? its not in the f100 diagrams i plugged the male and female plugs together by elimanating the diode and the wipers now have 2 fast speeds and it now parks.
i did not think this would slow down the speed??? i was under the understanding a diode only let the current go 1 way ??

 

> i was under the understanding a diode only let the current go 1 way ??

That is called a zener diode.

What you are looking at is probably a type of (ballast) resistor.

It is there to drop the voltage from 12v to about 9v. If you ever jump start a vehicle with the wipers on or have the wipers on while the battery is charging a dead battery, you can blow them. They can fail after time because the heat has to go somewhere, which means they break down.

You can replace that whole setup with a more modern setup if you choose. I think there is an article from the tech section that lays it out. Basically you just replace everything with an 80s type setup and grab the module behind the dash and wire it in. On yours, I would hazard a guess you need the more modern two speed wiper motor too.

 

to be correct: a diode is a two-terminal electronic component that conducts electric current in only one direction. it will conduct in the other direction when its "breakdown" voltage is exceded. which is kind of like you over-revved your motor and broke the crank ie, it is its max rating.

A Zener diode is a type of diode that permits current not only in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the its breakdown voltage (known as Zener voltage or zener breakdown voltage). this breakdown voltage is by design and can be any value the designer wants. it's kind of like a check valve in one direction - a 5 volt zener wont let anything past it until 5v is exceeded. if you wired a zener from a 12v circuit to ground, it would try to dump voltage until the circuit was only @ 5v. like a voltage regulator. generally its ability to carry(dump) large amounts of current isn't there. a 1watt zener could only pass .08 amps @ 12volts...

A conventional solid-state diode will not allow significant current if it is reverse-biased below its reverse breakdown voltage.

 

i get how the diodes work i just dont get why the f100s dont have them

 

the diode is in this e100 schematic but not the f100

 

sorry, not intending to sound like a ****** or preachy.

interesting but i can't comment as i do not have the f100 schemo for comparison. but it looks like the e100 requires power on both low and high leads for the motor to do the high speed. maybe the motor is different in the f100... might also have to do with the park feature in a wiper motor.

neil