Check your "hidden" AC fuse.

Mine had a serious meltdown but the fuse itself never blew (broke when I tried to remove it). The connector behind it doesn't look very good either.
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Pretty crazy for sure.

I've heard of one or two 348s with dash fires and I suspect that this may have been the cause.

 

Good grief, gonna check mine soon since I have used it twice. My drivers window switch light is intermittent mostly off as I have driven in the rain several times. So is dome light. Haven't done the connector treatments all around.

 

Certainly happens to almost all 348s, but doesn't it seem strange that there is enough current draw to melt the plastic, but not the fuse itself? One would think that they would design the plastic surrounding a fuse to be able to handle a higher current than the metal fuse itself to avoid this kind of situation.
I also am always amused when working on the car how every screw and nut, no matter how inconsequential, has at least 1 if not 2 washers under it, but when it comes to the wiring it must have suddenly been time to cut the budget. Wish they has spent more on the electronics than the plethora of washers.

 

I have the same think to my 348b.

The AC compressor is out and this fuse burned.

I have change the compressor and replacer this 30A fuse with 3 different fuse :
- one only for the AC/heating ECU (5A)
- another for the heating box hit the fan (10-15A)
- another for aliment the AC compressor (20 or 30A)
with this montage, each composant is separatly protect with an adapted fuse.

 

When you see this in home wiring it always due to a loose connection between the wires. As the arc creates heat it will melt a wire nut/insulation fairly quickly.

So who can post pics/description of the most common permanent fix? Are people going with an "in-line" type barrel fuse, splicing on a replacement spade holder/fuse type or?

 

I'd like to see the responses to this as well. Previously someone suggested a plugin relay instead.

When I do my repair the plan is to relocate this fuse to an area that's more accessible.

 

There is a TSB from the mid 90's from Ferrari that recommends a repair with something like posted above. I still have to do mine and am glad the OP reminded me. Thanks so much.

 

I think this may have been the first job I had to tackle on my old 348, back around 2001. Before I had ever heard of Ferrari Chat. The first time I drove my car, it was apparent that the climate control system didn't work at all, and I took something like $3000 off the dealer's asking price because of that. Had to diagnose and repair it for myself. I still have the old, melted fuse here in my desk. I installed a stereo fuse and holder, like the one shown above, and as far as I know, it's still working today. As I remember it, this fuse isn't shown in the owners handbook or in the workshop manual - is that correct? It's certainly in a ridiculous location, where you have to remove the trunk liner to get at it!

 

Yes you are correct, it is not shown in the factory material. I had the exact same experience that you had in purchasing my car. The only thing that didn't work was the AC and because it had been written up here and a few other places I was able to get a reduced price knowing it was probably the fuse. The first thing I did after purchase was to pull the trunk liner and there it was, a blown 30amp fuse. Replaced that and ice cold air.

 

On a side note, are you guys still using R-12? Or converted?

 

This hidden fuse issue is common

 

I'm still using R-12 because way back in the early 90's just before they made it mandatory to have a lic. to purchase 12 I bought one of those 20lb jugs of it at Sams Club. Would you believe it was something like $25. I still have about half and that is reserved for the 348 so I am good to go for awhile. I converted my 964 P car over to 134 about 15 years ago and it is not as efficient as before so I am going to stay with 12 for as long as I can in the 348. 12 is still available but a little costly.

 

Thanks, I'm thinking about going back to R-12 (currently has Freeze 12*).

But first I need to understand and determine my car's failures.

Prior to my ownership:

7/10: Charged A/C (R-12)
7/12: Replaced recirculation flap motor
7/12: Charged A/C (R-12)
8/12: Replaced blower control unit
5/13: Charged A/C (Freeze 12)

Recently:

8/14: Found melted "hidden" fuse


* "Freeze 12. Supplied by Technical Chemical, this blend contains 80% R-134a and 20% HCFC-142b."

Alternative Refrigerants for R-12

 

That is an interesting web site and has some real good info about the stuff that is out there currently. It appears that you have needed to recharge on a regular basis so you may want to do a leak check. When I did my major they rebuilt the compressor because the bearings were getting rough sounding. Of course they replaced the main seals and the rebuilder didn't do a good job and two months later all the refrigerant leaked out. You may want to look at that area first. Another thing I have read is the 134 of course has a different molecular make up and I believe the molecules are smaller and weep through the old style hoses. Since the replacement 12 you are using has a large percentage of 134 this may be the reason for the need to recharge. I have seen replacement hoses being marketed for other makes of cars to address this specific problem. Good luck in getting it corrected.

 

I did this back in '07, not an issue since...

http://www.ferrarichat.com/forum/348-355-sponsored-bradan/178507-hidden-fuse-exposed.html

 

Excellent! Thanks for that and now it's my project for this coming weekend. However, I plan to relocate my hidden "Maxi" fuse so that it's accessible from under the right cover.
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Can anyone give me a quick answer as to what this connector is for? I'm just starting to install a MAXI fuse and holder (to replace the hidden fuse/holder) but noticed this burned connector nearby. The connector has only two larger wires, black and brown.
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Some wise person changed the one in my Challenge.
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Okay, found it and the "hidden" fuse in the wiring diagram.

The brown (M) wire begins from the positive terminal on the battery (152) to this connector* (21), then to the hidden fuse** (69) and then to relay*** (68). All of these items on my car, except the battery, are burnt/melted.

* 21 - Connector between dash-board harness and air conditioning system
** 69 - Air conditioning system protection fuse (30 A)
*** 68 - Relay for evaporator fan motor

First I'll replace all of the burned components and then determine the next problem, if I still have one by then.
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