Fuse #32 keeps blowing?

Hi,

Wow, that fuse powers a million things. (Pic 1 below). Does it blow as soon as you install the new fuse or does the key need to be turned on? Also, since it was hot, chances are the AC was on. Do me a favor. Remove the compressor relay and see if the fuse still fails.

Let me know.

Joe

See pic below.

Thanks for getting back to me Joe. The vehicle needs to start for it to blow. It won’t blow with just key in the ON position. Also, where is the relay you’re referring to on the vehicle? I don’t have anything that looks like that diagram. It’s a 2006 expedition and there’s only one fuse box that’s below the glove box .

Hi,

We can skip the relay since it doesn't fail until the key is in the start position. Just to confirm, the fuse fails when the key is turned to the start position, correct?

If the fuse fails after you release the key, we need to start disconnecting one thing at a time that the fuse powers. If it fails as soon as it is in the start position, it will likely be related to the starter circuit.

As far as the auxiliary junction box, see pic below for the location. It's on the driver's side front.

Let me know. Sorry for more questions, but I'm trying to narrow things down.

Take care,

joe

See pic below.

Joe,

I double checked and found that the fuse does blow when key is in the on position and not start/run position.

Also, i took pics of what i thought was the box you were referring to, but it did not look like the original picture you sent, so I wasn’t sure where the ac relay was. And there were no markings on the cover to indicate either.

As far as unplugging everything one by one, can you send me the diagrams of where everything is? I know where the oxygen sensors are but some of the other things i don’t know.

Thank you so much for your help!

Is the ac clutch relay the grey relay in the photo i sent?

Hi,

It appears to be the relay. Isn't it interesting how they hide things? Ugh!!!

Do me a favor. Remove the relays in the CJB and see if it still fails. The relays are what actuate several things related to the fuse.

I have a question. My manual is showing two fuse boxes. One is the central junction box and the other is identified as passenger compartment fuse panel.

If you look at pic 2 below, that is the passenger compartment fuse box. If you have that, remove the relay that I circled first. Pic 3 is what I'm finding.

Let me know.

Joe

See pic below.

Hi Joe,

Yes, i have the passenger compartment fuse box as seen in pic 2.

I will work on it when i get home.

In case doing what you mentioned doesn’t work and i have to start unplugging everything one by one, can you send me the diagrams of where everything is? I know where the oxygen sensors are but the other things I don’t know.

That would really be a great help. Thank you, Joe, for helping me.

I removed all relays in the CJB and fuse still failed. I removed relay #203 you circled from passenger fuse box and fuse did not blow. I believe r203 supplies power to f32 correct? So, it wouldn’t matter if I removed r203, right?

I was going to plan on start unplugging everything connected to f32. Could you help with those diagrams of where everything is located?

Hi,

Actually, the fuse supplies power to the relay. Switch that relay with a different one having the same part number. See if that makes a difference. See pic 1 below.

Joe

See pic below.

What you suggested didn’t help. Fuse still blows.

Hi guys. I've been vibrating in my seat waiting to learn the solution, but I see you've been wasting a lot of fuses. Please allow me to add my trick that will solve that. Use a light bulb in place of that fuse. All that will happen is when the short is present and the circuit is powered up, the bulb will be full, normal brightness. It will get hot so be careful where it's laid, and it will limit current to a safe value. My drawings show using a common 3157 brake light bulb. That will allow up to one amp to flow. Once the short is removed, the bulb will get dim or go out and the circuit will resume trying to work. If the bulb limits current too much, you can use a head lamp bulb instead. That will allow up to five or six amps to flow.

While this works great for fuses, I'm posting the procedure for bypassing a relay instead. I see a lot of mention of that. By bypassing the relay instead of the fuse, you usually can power the circuit without needing to turn on the ignition switch or do anything needed for that relay to turn on. I made these drawings over-simplified, but that's easier than trying to describe what to do. You do have to install a good fuse.

Joe can elaborate on where to find the items I listed, and which relay terminals to use if yours look different than those in the drawings. You can do this just as easily at the fuse socket too if you prefer. I hope this will help you guys figure this out.

Thank you for your help, I greatly appreciate it! This problem is frustrating and time consuming and I’d really like to get to the bottom of it!

Joe, what is the next step?

Should i start unplugging everything related to fuse 32?

Hi,

Yes, if you unplug the components associated with the fuse, it should prevent it from failing. If it does fail with the things disconnected, then we have a short to ground at some point causing the fuse to fail.

Once you disconnect things, reconnect one at a time to determine which component is causing things to fail.

Let us know,

Joe

Do you have diagrams of where everything is located?

Hi,

As far as locations, the schematics don't provide that information. Is there something specific you need help finding?

Let me know.

Joe

I’ve got all the 02 sensors unplugged, but i need help locating everything else.

Hi,

I attached a pic of the PCM below. Before you disconnect the module, disconnect the battery negative cable. Also, disconnect the battery before reconnecting the module.

Let me know.

Joe

Wait, so I shouldn’t disconnect the items related to fuse 32? Should I disconnect the PCM instead? I’m a little confused.

Hi,

From what I'm seeing, it powers the PCM relay. We switched the relay before with no success. If you remove the relay, does the fuse still fail?

Joe

I don’t believe the fuse fails if the relay is removed. I thought we were unplugging everything related to fuse 32 which was in the very first photo i sent. Things like the o2 sensors, transmission solenoids, etc. then plugging each one back in and seeing if the fuse blows?
but I will follow your instructions if you think this is a better route.

Update…

Fuse does not fail if the relay is disconnected.

Fuse does fail when PCM is disconnected.

Hi,

If the fuse doesn't fail with the relay removed but does when you connect the PCM, closely inspect the PCM connector pins on both connectors to see if there are any damaged or touching/shorting.

The reason I said to disconnect the relay and PCM is because most of the things getting power is triggered via the PCM.

Joe

Pins on both connectors all look to be in good order.

Hi,

If the pins are in good condition, then either we have a short in the wiring between the relay and PCM or the PCM has an internal fault causing the fuse to fail. Are you able to get a good look at the wiring?

Let me know.

Joe

Joe, I’ve narrowed the problem down to a short in the wiring between the relay and PCM.

How should I proceed forward?

Hi,

The best thing to do is replace the wire itself with one that is equal in gauge and length. You will need to re-pin it to make it work with the connectors.

Is that something you feel comfortable doing?

Other than that, you can try going a little at a time piercing the wire to see where the problem starts and stops and cut the wire and splice it with a new section of wire.

Let me know.

Joe

I think I could replace the whole wire, seems easier. Do you have any instructions on doing that?

I believe the wire to be replaced is orange and yellow, correct?

Hi,

I'm not sure about the wire color of the one you found faulty. Also, the manuals don't provide directions for this type of repair.

Let me know.

Joe