"Option" on fuse diagram

[TheSheepKed]

'13 MN GLX (second hand)

Was poking around the cab fusebox looking for a spot to tap and noticed how odd it looked.
The blue fuse circled in red (15A mini fuse) just looked so out of place. I checked the diagram and it said it was a 10A slot for "option" which I have no idea what that means. So already wrong fuse in the wrong spot. Anyone know what "option" is?

Then I checked the fuse circled in blue (low profile 10A) and that is supposed to be empty (according to other people) because it powers rear window wipers which I definitely do not have.
So I swapped them around.

And then I flicked the ignition on today and the radio had reset itself and needed the code (which I have). Any idea why? I haven't been able to reproduce the radio reset. I don't recall pulling the radio fuse either. And when I did pull it and replace it, it still turned on as per normal.

I have a feeling the previous owner or someone in the past has replaced the fuses willy nilly. I can see plier marks on the 10A fuse. None are blown. Still all in good order.
Another weird thing is that there is only metal contacts on one side of that 'rear window wiper' slot. Is that normal for everyone else?
That is to say, one leg of the fuse will touch metal but the other will not. Hence is it ok to tap into that with one of those piggy back taps?

So I guess my questions are
1) What is "Option" and what does it power
2) What on earth happened that the previous owners had the fuses all jumbled up (everything else is ok)? And should I be worried?
3) Is everyone else's "rear window wiper" slot (the one circled in blue) empty? Because I have currently left it empty. And does it only have one metal contact in it?
4) Why did my radio reset?

Pictures of your fuse boxes would be much appreciated.

[explorer.dave]

I would guess that the rear wiper fuse is for Challenger models, AFAIK no Tritons came out with rear wipers. I would also assume that "option" is just for that, any other options you select from new, they would use that fuse space.

[NowForThe5th]

Was poking around the cab fusebox looking for a spot to tap and noticed how odd it looked.
The blue fuse circled in red (15A mini fuse) just looked so out of place.

Odd? Why? You are aware that there are two types of this size fuse? Standard and Low Profile? Fully interchangeable.

I checked the diagram and it said it was a 10A slot for "option" which I have no idea what that means. So already wrong fuse in the wrong spot. Anyone know what "option" is?

You need to understand that most cars use a common platform for different models which may have options dependent on market or model. Mitsubishi also share parts across different models. Yours is the bottom of the range so won't have options that the GLX-R (or other models) might have, but it's not worth Mitsubishi's effort to produce a different fuse box just for yours. "Option" may also mean a slot for dealer fitted options - so they can 'plug and play'.

Then I checked the fuse circled in blue (low profile 10A) and that is supposed to be empty (according to other people) because it powers rear window wipers which I definitely do not have.
So I swapped them around.

Define "other people" and why they would know what they're talking about.

And then I flicked the ignition on today and the radio had reset itself and needed the code (which I have). Any idea why? I haven't been able to reproduce the radio reset. I don't recall pulling the radio fuse either. And when I did pull it and replace it, it still turned on as per normal.

Radios have two power sources. One to turn the unit on and off, via ACC/IGN and the other to power the date/time functions - which need constant power, of course. If power from this source is interrupted then the radio thinks that it's been disconnected and will require entry of codes to operate. This is, of course, a security feature and why radios aren't stolen much any more.

Fuses are also often shared, but not always marked. So, your "Option" fuse is likely the power source for the radio which may be an option for your model, i.e. different to that on other models. Pull it out again, leave it out for a little while in case there is a capacitor to store charge, then put it back in and see if the radio asks for codes again.

I have a feeling the previous owner or someone in the past has replaced the fuses willy nilly.

Based on one fuse being of a slightly higher rating? Kind of leaping to conclusions, aren't we? What if the previous owner had an accessory that was powered on this circuit via a fuse tap, then removed the accessory and simply replaced the fuse? Maybe he didn't have another 10amp fuse or forgot that he'd moved the original to an unused slot. At the end of the day, what's the problem? You have a 15amp fuse in a 10amp circuit. Will make not the least iota of difference.

Another weird thing is that there is only metal contacts on one side of that 'rear window wiper' slot. Is that normal for everyone else?
That is to say, one leg of the fuse will touch metal but the other will not. Hence is it ok to tap into that with one of those piggy back taps?

It would be normal for any vehicle that doesn't have a rear window wiper. Could you use that slot for another accessory with a fuse tap? Certainly, if there's power available and at the right times on the connection that is there. You've likely stumbled on something valuable here since a wiper motor will consume a reasonable amount of power and the supply side of that fuse is likely cabled to take 15amps or more.

So I guess my questions are

...answered.

[TheSheepKed]

Blunt, but I like that. Thank you for your extensive reply, Chris.
I guess it's my turn.

Odd? Why? You are aware that there are two types of this size fuse? Standard and Low Profile? Fully interchangeable.

Very much aware of the two types of fuse. I thought odd because it was the only one that wasn't the low profile.

You need to understand that most cars use a common platform for different models which may have options dependent on market or model. Mitsubishi also share parts across different models. Yours is the bottom of the range so won't have options that the GLX-R (or other models) might have, but it's not worth Mitsubishi's effort to produce a different fuse box just for yours. "Option" may also mean a slot for dealer fitted options - so they can 'plug and play'.

I figured that might be it but just wanted to double check "Option" didn't mean a specific feature I had never thought about.

Define "other people" and why they would know what they're talking about.

Like two other people to be fair. Just had a look at a picture of their fuse boxes and there's nothing in their "Rear window wiper" slot, but mine did. Was wondering if it was a recall thing that a Mitsubishi mechanic had done, i.e. don't tamper with it.

Fuses are also often shared, but not always marked. So, your "Option" fuse is likely the power source for the radio which may be an option for your model, i.e. different to that on other models. Pull it out again, leave it out for a little while in case there is a capacitor to store charge, then put it back in and see if the radio asks for codes again.

I'll give this a go.

At the end of the day, what's the problem? You have a 15amp fuse in a 10amp circuit. Will make not the least iota of difference.

Fair enough, maybe I'm just a stickler for having things in the right spot doing what they're meant to be doing.
Regardless, the 10amp is back in its rightful place.

It would be normal for any vehicle that doesn't have a rear window wiper. Could you use that slot for another accessory with a fuse tap? Certainly, if there's power available and at the right times on the connection that is there. You've likely stumbled on something valuable here since a wiper motor will consume a reasonable amount of power and the supply side of that fuse is likely cabled to take 15amps or more.

I guess it makes sense that there's not a fuse nor another metal contact for it. But I just want to know if other people's vehicles with the same year and model have nothing in that spot. Just bugs me that there was a fuse in there (albeit wrong amp) and now there isn't since I took it out.

If I'm thinking this right, there can't be anything running off the 'rear window wiper' fuse line because there's only one metal contact in that fuse slot (12V battery side/hot) and so even if there was a fuse in there, there's no draw/cold side?
Right?

Thanks again mate.

[TheSheepKed]

Pull it out again, leave it out for a little while in case there is a capacitor to store charge, then put it back in and see if the radio asks for codes again.

You were right - I pulled the fuse out and left it out for a bit. Put it back in and it went to code.

There was a small spark when I put the fuse back into that "Option" slot. Should I be concerned?
Or is that expected?

[NowForThe5th]

Blunt, but I like that. Thank you for your extensive reply, Chris.

Some don't. No problem - I figure I'm not just replying to your questions but to all those who read this thread subsequently.

If I'm thinking this right, there can't be anything running off the 'rear window wiper' fuse line because there's only one metal contact in that fuse slot (12V battery side/hot) and so even if there was a fuse in there, there's no draw/cold side?
Right?

Nailed it.

There was a small spark when I put the fuse back into that "Option" slot. Should I be concerned?
Or is that expected?

The circuit is not switched so when you reconnect by inserting the fuse there will be a small spark.

[TheSheepKed]

Cheers for that mate.

I've had a look at the wiring diagrams. The only thing I can find for the "Option" fuse is for an amplifier which I don't think the standard GLX has.
So that might be the "Option" we're referring to. (See red circle below)
I still can't fully work out how it links to reset of the radio but it must be part of the circuit in some way even if it's there as an extra.

See what you think.

No amplifier vehicle


Amplifier vehicle

[RHKTriton]

Further to your PM, sheep'; if you have an unpopulated fuse position that has a live terminal, you could use a piggyback fuse holder to turn that into a fused supply.

That way you don't have to load anything onto existing fused circuits.

[NowForThe5th]

It's this bit (from your first diagram)

Screenshot at 2018-04-04 18-04-40.png

...and, at the fusebox:

Screenshot at 2018-04-04 18-10-01.png

[TheSheepKed]

Further to your PM, sheep'; if you have an unpopulated fuse position that has a live terminal, you could use a piggyback fuse holder to turn that into a fused supply.

That way you don't have to load anything onto existing fused circuits.

I'm not sure I understand what you mean by that?
Are you saying that for example if we take the rear window wiper empty slot, we can convert that into a normal fused supply by just putting a single fuse in that piggy back holder (e.g. 2 - 3 amps for UHF) and connect the red/positive from the UHF onto the wire that comes out of it?

It's this bit (from your first diagram)

Screenshot at 2018-04-04 18-04-40.png

...and, at the fusebox:

Screenshot at 2018-04-04 18-10-01.png

Geez that sounds pretty important. Not quite "option" is it? I'm paranoid the little spark that happened when I reinserted the fuse caused a short. If I blew that fuse that we're now looking at, my radio wouldn't be working would it? Nor would my door lamps? Or my AC?

[NowForThe5th]

Are you saying that for example if we take the rear window wiper empty slot, we can convert that into a normal fused supply by just putting a single fuse in that piggy back holder (e.g. 2 - 3 amps for UHF) and connect the red/positive from the UHF onto the wire that comes out of it?

Yes, that's exactly what he's saying. But you need to make sure that you put the fuse tap in the right way around, so that the current flows through the fuse. Have a look at this diagram (shamelessly taken from Google images):

Screenshot at 2018-04-04 21-24-55.png

If I blew that fuse that we're now looking at, my radio wouldn't be working would it? Nor would my door lamps? Or my AC?

Correct. But don't panic. A spark doesn't necessarily indicate a short, just the flow of current which jumps the gap in the moment before the fuse makes physical contact with the socket.

[TheSheepKed]

Yes, that's exactly what he's saying. But you need to make sure that you put the fuse tap in the right way around, so that the current flows through the fuse. Have a look at this diagram (shamelessly taken from Google images):

Screenshot at 2018-04-04 21-24-55.png

Yep got it. Based on that diagram though, the 2 or 3 amp fuse would have to sit in the slot in line with the wire that comes out otherwise if it was in the slot closest to the prongs, then it would essentially just be fusing nothing since there's no metal contact on the cold side of the 'empty' fuse slot that we've been talking about (rear window wipers).
Alternatively I could just put the original 15amp fuse on the bottom slot and the 2 -3 amp fuse on the top just so it's safer although I have a feeling it won't change anything.

Positioning wise, since the only metal prong in that slot is at the top, that must be the 12V/hot side and so the fuse tap wire will have to be on the opposite side to that.

Correct. But don't panic. A spark doesn't necessarily indicate a short, just the flow of current which jumps the gap in the moment before the fuse makes physical contact with the socket.

Fair enough. Made my heart skip a beat when I saw it. I was sure I was in for a $3000 repair.
I need to be careful with how many times I switch the ignition on and play with power because the car definitely took longer to start today, almost sounded like a drained battery.

[NowForThe5th]

I think you just passed Auto Electrics 101.