I have an intermittent electrical problem in my 2002 F150 and need help.
I turn the engine off and remove key but still have power to the fan and radio. The battery usually drains overnight. It used to only happen a couple times a year when weather is very cold. Now it happens fairly regularly.
I pulled the key cylinder completely out and still had power to fan and radio.

Any suggestions??
I’m no mechanic so I need any help I can get.

If the key is in the off position but power is still going to the blower, I would think the switch is where the problem lies. Is there any other areas I should look at??

I’ll pull the ignition switch and test continuity based on a continuity diagram I found online. Maybe that will show something.

Because it’s an intermittent problem, I might have to just replace the switch and see if/when my battery dies. —But I hate the idea of spending money to swap out parts in hopes it will fix the problem.

 

You said you can handle removing ignition lock cylinder, so I assume your steering column shrouds (upper and lower) are already off. Do you have a voltmeter so you can test the continuity of your ignition switch? Do you also have alligator test leads?
You said yours is 2002 F150, please check my signature and complete your 1st line when you reply this.

 

Maybe,,,
Suggest you consider using a test lamp because you can easily see just what the switch is doing while driving .

Verify where power comes in to the switch ON the lower part of the steering column near the brake pedal. Then find the terminal that gets power when the key is in the on position.

If you place the ground clamp on that wire,and stick the pointed end of the test lamp to any convenient ground point (sheet metal) that allows you to see the lamp while driving. If it fluctuates you have just verified the switch is the problem.. Most sw assys have slotted holes to adjust the correct position so the vehicle only starts in park or neutral. position.

Be careful when removing or installing the tumbler section, there is a gear that indexes with a toothed rack that activates the ign sw assy.
If moved out of the correct position the can of worms gets opened.

 

Thanks for all the feedback. I’ll take it as far as I can and give an update of what I find.

Side note: In 2019 someone posted this same problem I their 2002 F150. So I’m not the only one that’s experiencing this problem. Unfortunately there were no replies to the post back in 2019.

 

If you need diagrams and instructions (alldata service manual, identical to ford repair manual) please check my signature on how to....

 

Update:
I removed the ignition switch and tested continuity per the attached diagram. No continuity problems found.
The quest continues.

Somehow the dash is getting power when key is in the off position. In my very inexperienced opinion, I thought the switch would be the problem. But that doesn’t seem to be the case.

——This is an intermittent problem which makes it even more frustrating. #!%#$#!