A few weeks ago, I noticed when I was driving down the road how the interior lights would flicker on and off and was also hearing this clicking noise that appeared to be coming from down by the door that coincided w/the light flickers. With this being an older truck (1997 F350), it still has the old style switch that activates interior lights on/ off.

I assumed that changing out that switch would do the fix. Unfortunately that didn't work. I even tried switching out the fuse that controls the interior lights, it didn't work. Just for reference, it is Fuse #13. If I remove this fuse, the lights do go out, but I can't drive it that way even though the description for that fuse shouldn't be linked to the turbo/ power for the truck but somehow it is because it's not drive-able w/the fuse gone which is why I tried swapping it out. The cruise still works and everything else from what I can tell. It's just the clicking noise, the flickering on/off of the interior lights and the light on the back of the cab for backing up.

Any suggestions on where to start trouble shooting this issue? Do you think its electrical or ???? While I am pretty self-sufficient, I do not have the skill to do much diagnostics. Just trying to get some ideas and have a couple of friends that can help if they know where to start looking. I can't afford to take it to the dealer.

 

Why can't you drive it without the interior lights? Or are you referring to the dash lights? The interior lights are the dome light, the courtesy lights in the doors and the bed lights in the cab roof. The lights on the cab roof do not go on while reversing.

When you replaced the headlight switch, did you inspect the connector? That switch is famously (notoriously?) under-engineered, known for causing trouble because of the full current of the headlights going through the switch. Sometimes it's not just the switch that's damaged as a result, but the terminals on the connector. That's where you may be shorting something. Did you see any signs of electrical burning/damage on the connector?

What year truck, BTW?

Oh wait, what do you mean by "not driveable"? Do you mean the engine doesn't start, or some necessary lights don't work, or something else?

 

No, what I said is that with the #13 fuse removed, it is not drive-able. It is a 1997 F350 truck and it needs this fuse to have any power. It will start but there is next to no power W/OUT the fuse. And, I did not replace the headlight switch. I replaced the fuse in location #13 as show in the diagram.

The fuse is in a control panel like what I attached in my original post. There are no signs of burning in the control panel. It is not connected to a terminal, it is to my left in the driver cab.

 

What do you mean by "next to no power"? Does that mean weak voltage to some circuits? Or does it mean some circuits do not work? If it's the latter, exactly what does and does not work with the fuse removed?

Did you replace some switch or not? If so, which one?

 

I had someone replace the switch inside the driver side door and also tried the passenger side door that in the older vehicles tells the interior lights to go/off when the door opens.

Let's not worry about the lack of power. It's only relevant if the fuse is not in place and it always is when I drive it. I was only removing it because the lights would not go off sometimes after I shut off the truck and I didn't want to wear down the battery. I drive it just fine w/the fuse in. There is a clicking noise like some wire is touching something causing the short.

 

That switch is in the door jamb. Probably the harness going to that switch has a chafed wire. You can pull it out part way and inspect part of it by removing the switch. You might be able to get to more of it by removing the trim panel on that side of the cab.

Is this a crew cab truck, by the way? You should check the switches in those door jambs too, if so.

 

Thanks. Yes, it is a crew cab. It's a 97, but only has 115K original miles. I've owned it since 99 and only use it to go to horse shows and haul the occasional farm stuff.

So, your thinking possibly the wiring behind the door jamb? When the guy replaced the door jam on both the driver/ passenger front, I don't think he saw anything unusual but I will have to ask him for sure. I hauled a couple horses today and now think the clicking noise might be coming from somewhere behind the dash which I know is not good. Taking apart the dash is not a fun job from what others tell me.

 

What you're hearing may just be the symptom. The cause may be one of the harnesses going to one of the door jambs. Unfortunately with a crew cab, you have twice as much to check.

 

Ok, thanks. I'm thankful this doesn't prevent me from driving the truck, just highly annoying. It's been an awesome truck for me.