Hello everyone,

So I'm trying to track down and fix the cause of this fuse #34 blowing whenever I plug something in. This just started happening and I haven't made any changes to the truck. It worked fine before. But now anytime I plug anything in the fuse blows.

I don't believe it's because of the devices I am plugging in, because they have all worked fine before. I have tried with just a usb charger that has a light that comes on when plugged in, a usb charger without a light, and a dash cam.

I have checked the wires from the power point up to where they join the rest of the harness and there are no bare spots I can see where it might be shorting out. If the power point is disconnected the fuse doesn't blow. If the power point is connected and I don't plug anything in, it doesn't blow.
I have tried replacing the power point with a new one, but the same issues occur.

I tested for continuity from the power point to the interior fuse box and there is continuity. The other power point on fuse #29 works just fine with all of the aforementioned devices. Does anyone have any suggestions on what I should look for/test next? Any advice is appreciated

 

Are you sure you are using a 20 amp fuse ?

 

Yes Sir. It had been working fine for about a year and a half then it just quit. Now anytime I plug anything in, it blows the fuse almost instantly.

 

Check for continuity between the pos and ground for the power point? Sounds like its shorting out every time you plug something in. One probe on the power point side wall and the other on the power point center base should read open.

 

Yes I have checked for continuity in the power point socket itself (if I understand you correctly) and even replaced it and have the same issue.

I also found a wiring diagram and have found the ground on the left side wall under the e brake and have continuity from the power point to the ground, and even from the fuse socket to the ground.

I might just end up pulling the dash out so I can actually get to everything. But that's a chore

 

Pull out fuse 34
Use volt meter to find which of the fuse slots has the 12volts, the OTHER slot goes to the power point
Test the OTHER slot with OHM meter, should be no connection to ground, of course, if there is then wire from fuse to power point is shorted to ground, BUT...............that WOULD drain the battery since this fuse has full time 12volts, and you don't mention that

Assuming no short to ground, then plug something into the power point, you should see 100-200ohms depending on what you plugged in, you can test your USB light first to see what OHMs it has, then plug that in and you should see the same OHMs
If ohms drop blow 8 there is a short in the power point, don't care if its new

???????
If you have continuity from fuse to ground you have a short

 

To clarify, here is the wiring diagram with the points I tested for continuity.


So I went to measure to find which of the fuse slots is 12v, and I suddenly have no voltage OR continuity at the fuse socket with the fuse removed. With the fuse in place it measures continuity, but no voltage. I still have voltage at the power point itself. I have no idea what's going on here

 

Then fuse 1 in engine bay is blown

In second diagram there should be NO continuity between the arrows, if nothing is plugged in to the power point
If you plug in your USB light then you should see OHMs above 100, NOT continuity, you need to see RESISTANCE, a short is 0 resistance, OHMs under 8

 

The 12V Power Port and the Cig Lighters wear out, depending on how many time you push-in and pull-out a Plug.

I don't think they are too expensive, check them both out and replace both at the same time, it will save you some time.

THINKING HERE..., smell the wood burning, IF the Cig Lighter and the 12V Power Port mount the same way and have the same connectors, I think the Cig Lighter would be a better choice for both locations. It was designed to have the Lighter Portion slid in and out a lot more than the Power Port and it handle the heat better.

 

Ok so I am a novice with this electrical stuff so I want to make sure I understand this part correctly. I went out and tried to measure the fuse slots again today and the TOP one is 12v. So then from here, I should test with OHM meter in the BOTTOM fuse slot, and the other end to the outside of the power point which is the ground, is that correct? If so, I am getting .3-.4 OHM measuring. But I have not had any issues with the battery draining. I also tested to the G205 ground shown by the bottom red arrow in the pics and it has the same .3-.4 OHM. I tested the usb charger and it also tested at .3-.4 ohms. on its own. With the charger installed, it also tested at the same .3-.4 OHMs. So it looks like I have a short to ground. Is that correct? I have not had any issues with my battery dying

 

First lets test your OHM Meter, something is wrong since its showing same thing on each connection
Set OHMs at 200 if you have that option on the meter
Then touch the two probes together, should see 0 ohms, no resistance, direct connection
Then go to battery and test OHMs from negative battery terminal to any engine metal part, should see 1 to 3 ohms, some resistance from the wire/metal distance, still a short

Then test USB light or any light bulb should see 100-300ohms, higher resistance so not a short

Yes, test from Bottom slot of fuse holder(non-12v slot) to the G205 ground should be NO CONNECTION, OHM meter shouldn't change at all
That slot and the ground point are NOT connected until you plug something IN to the power point

Lower Fuse slot----------------------power point |....|------------------------ground

|....| = open, no connection, until something is inserted to connect them

And that something needs Resistance above 50 ohms or its a short