Melted fuse

[Ando81 2,949]

Hi all, just found this melted fuse on the floor of my xf ute. It was a 20amp out of the heater- ac fan position. It was still working when I found it. The fuse had melted and fallen on the floor sometime over the past week. Because I have been working night shift going to work in the dark I hadn't noticed it but today in the daylight I saw it. I did have the ac fan on flatout for about 20mins the other day after a hot shift at work, was either that or when I jump started my xf sedan today, I had my ute running and the fan on low speed when I jump started it but don't think that would have done it. Any suggestions? Should I be concerned?

[Mr Polson 10,214]

A melted fuse would concern me, would take a bit to happen I reckon.

 

Put a new one in see if it blows again?

[Xelisty 366]

Check the contacts on the fuse panel. If they look slightly corroded that can cause that too. If clean and very good connection likely a bigger issues. With heater/motors they can gradually get worse or high resistance joints causing this so it may not bee nought to blow the fuse.

Check connections. Check with a multimeter the resistance of the heater

 

 

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[Ando81 2,949]

Cheers lads, I've put another 20 amp in for now. Might put in a 10amp tomorro and see if I can get it to blow. All the contacts on the fuse panel are spotless and look great. It even started to melt the black plastic on the fuse box contact.

[Outback Jack 6,352]

heya Ando, If ya melting stuff its a short in the fuse panel at back or the fan motor or wiring to it is shorting somewhere.

 

Jack.

[Ando81 2,949]

I thought a short would blow the fuse straight away Jack.

[Outback Jack 6,352]

Nope Ando sometimes they don't. In theory all fuses should protect but in reality sometimes they fail badly.

Just had a dead short on a set of spotties, Positive and Negative connected at connector behind spotties, melted the globe leg and melted the fuse just like that.

So badly melted the fuse couldn,t even be removed.

 

Hope ya find ya short.

 

Jack.

[Ando81 2,949]

Well bugger me, I reckon you're spot on then mate, cheers. I best go and hunt around for it then.

[Outback Jack 6,352]

It might take a lil time to narrow down Ando , can be a pain in the arse, but be good to know where it happened.

Fans use a fair bit of power so could be main positive for that shorting somewhere.

Happy hunting.

 

Jack.

[Ando81 2,949]

Hmmm, a bloody tone sender would be handy for that. Just gotta try to track it down with my multimeter instead.

[Xelisty 366]

If the meter does not work Alternatively use a spade terminal in the fuse power via a 240v decent wattage bulb, bit of wire and the other on the other side of the fuse.

Turn on ignition /fan and it will shine bright as. Make sure only a second at a time.

Then disconnect the wiring to the fan and try again and see if it glows big time.

If not glowing bright as likely the fan/heater stuffed.

Replace it and try again.

If so the wiring is the fault and you need to start hunting for terminal strips, connectors, burnt wiring etc and work your way back to the fuse panel.

 

Make it very clear when testing strictly on the off straight away or you risk wiring or damage.

Don't leave it on and wander around the car pulling wires . Not safe enough

 

 

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[Ando81 2,949]

Well I didn't get a lot of time to do much testing today but I replaced the 20 amp fuse with a 7.5 amp. I ran the fan on low speed and it created minimum heat in the fuse, soon as I ran the fan on the highest speed it heated up rapidly. I'm thinking the fan motor might be on the way out.