Quick trip to Ace turned into a head scratcher. Why would these 3 issues occur simultaneously ?

Door Ajar lamp stayed on. Double checked all doors.
Electric door locks would not function.
Windshield wipers would not function.

All other electrical functioned as normal. According to the fuse chart they are separate fuses but even if it was a fuse that doesn't explain the door ajar light.

This issue has plagued me off and on for quit some time and I cannot figure it out. Any help is appreciated.

David

 

They are separate fuses fed by a fusible link that's hot at all times. However, that power feed to those fuses also powers a couple dozen other circuits so it's very likely not a problem with that fusible link since the listed concerns are all you have.

The wiper motor is controlled directly by the multifunction switch on the column.
The dome lights are controlled by the instrument panel cluster so a scan tool that will access the data there will have to be used to see the inputs to that control module.
The door locks are controlled by the vehicle security module, keyless entry or not.

There is one common denominator to them all though. They all have an input from the ABS module for vehicle speed. This doesn't explain the dome lights always on, but the vehicle speed will cause them to turn off after a few seconds at a slow speed (I want to say 10-15 MPH) but I haven't looked into this issue too many times.....60% of the time it's a door latch switch every time. Also, the vehicle speed is used to LOCK the doors at speed (unless you've disabled that stupid feature). Why the wiper motor needs it, I don't know.

 

I kind of remember some of the trucks, maybe it was only Lariat and some other high trim packages had speed sensitive intermittent wipers. I'm pretty sure there were two different multifunction switches depending whether the truck had that option or not.

 

Ah, another "feature" forced onto the buying public that nobody asked-for or needed.

 

As mentioned above the door latch switch is a pretty common problem. IIRC the fix is hit it with WD40 and open and shut several times. Easy first fix attempt.

This thread has pics and info.

The infamous door ajar/ No power lock saga - Ford Truck Enthusiasts Forums

 

Mine is a Lariat but the wipers are just Low, High and Intermittent but yesterday the would not come on at all in any position.
David

 

I can say without a doubt that I am in uncharted territory. This issue is above my head and there is nowhere local that I trust to take it to. Hope to find some sort of breakthrough here.
David

 

Electrical problems are difficult, if not impossible, to diagnose simply on symptoms. Inspection, measurements and testing are usually required.

Try to fix one problem at a time. I would start with the door switch. Maybe they are all related, but probably not.

Use this link to get wiring diagrams.
https://lemon-manuals.la/Ford/

Once you are into the diagrams and are checking voltages etc, the forum can help.

 

I sprayed the door latches generously with WD40 this morning before I left for work. I'll let them sit today and check to the door ajar light tonight.

I also noticed when I opened the driver door that the dome light would not come on....... Frustrating.

 

To help me diagnose further which wired Forscan reader should I order?


Thanks! David

 

The OBDLink EX is the one most ppl use with ForScan.

When I follow that link, I get this . . .

 

So odd. This is what the link should have directed you to. Sorry, don't know what happened.

 

It gave me the same thing again. Weird.

 

That is so weird! Let's try this. Thank you for your help @Pikachu !

 

that is what I bought 2+ years ago, I tried 3 Bluetooth dongles and none of them worked.