This morning I went to start up my 2008 mustang 4.0L V6 only to find that my windshieldwipers did not work, how ever after tampering with them for a while i found out that they worked but only at the highest speed and when I would go to turn them off the wipers would abruptly stop in the middle of my windshield causing obstruction of my view. Not sure if this is a wiring issue or a bad fuse, I just find it very odd that the wipers still operate but only on the highest speed. Any guidance on this topic would be greatly appreciated!

 

From what you describe, it could very well be a fuse going bad, a module/relay going bad, wiring issue or all the above. Until having the electrical system tested, your not really going to know for certain..
Therefore, I'd start out by using a voltage meter and check your wiring harnesses, fuses and relays.. If the voltage meter test isn't effective? then your next option is having your electrical system diagnosed by either a Ford dealer or auto repair shop which has expertise in automotive electrical systems.

Meanwhile, sorry that I wasn't able to provide more info, but for what it's worth, hope you may find the info provided as at least somewhat helpful.. Best of luck and welcome aboard.

 

Here is the wiring diagram for the wipers and washers, from stick to motor:

https://iihs.net/fsm/?d=40&f=Wipers%20and%20Washers.pdf

You'll notice the motor has electronics in it to determine how to work. You'll need to do diagnostics to be sure, but the causes are:

Multifunction switch is unhappy.
Motor electronics are unhappy.
Wiring is unhappy.

Here's the diagnostics:
https://iihs.net/fsm/?d=469&f=Wipers...%20Washers.pdf

However, what you can do quickly enough is do some continuity, power, and/or ground checks. The connection in the wiring at C211 or C125 could be crusty and/or just not connecting right, so using a mulitmeter is going to be a good first check.

Here's the location diagram for those connectors, by the way:
C125, left side rear engine compartment (at the motor):
https://iihs.net/fsm/?d=40&f=Compone...on%20Views.pdf
C211, Left side under dash (at column/firewall):
https://iihs.net/fsm/?d=40&f=Compone...0Views.pdf&p=6

My gut call is the wiper motor itself, but that's from *WAAAAY* over here in my computer chair, so again, diagnostics. Do them. It'll point you right to the cause and what to fix.

Hope that helps, and good luck! Welcome to the forums!

 

"What he said"

 

UPDATE!

Interesting Info Here!

https://themustangsource.com/forums/...4/#post7088274

Kc Admin