Ferrari 348ts 1991 Heating System Problem

Do a search in this section, there are dozens of topics on the subject.

 

Maybe you can find som info here: http://www.club348.com/technical/Tech/348.html#AirConditioning

 

John: There's about a 90% possibility that your problem is the "hidden fuse" under the front trunk lining. There is also a possibility that you have a bad/dirty connection at the back of the heater control unit on the center console, or an internal problem in the heater ECU.

You see, Ferrari placed the main fuse for the A/C system in a silly place where you can't easily get at it, and they don't bother to tell you where it is when you look in the Owners Handbook or the Workshop Manual. To make it worse, they used a blade fuse with a small contact area for a system that draws a lot of power, and the fuseholders have a tendency to melt. That's better than melting the wiring harness, but it's not very good engineering. The fuseholder can melt without even burning out the fuse. The proper repair is to replace the fuseholder with one of the large glass fuseholders used for stereo amplifiers.

Do a search with the words "348 heater fuse". And welcome to Ferrari Chat!

 

Is your car left-hand drive? What do you mean by "that location"?

The fuse should be under the trunk lining, on the passenger side of the fresh air inlet box, just in front of the two green relays. It's the green 30amp blade fuse that has a heavy brown wire going in and out of it. There is no reason why the fuse should be anywhere else.

You can get a limited view of the fuse by pulling up the rubber seal around the corner of the trunk and lifting up the lining, but you really need to remove the entire trunk lining in order to work in that area.

 

There is one fuseholder in there that isn't supposed to have a fuse in it - the one for the diagnostics on the ABS circuit. You want the fuseholder with the big brown wires, near the green relays. It SHOULD have a green 30amp blade fuse in it. If you ARE looking at the fuseholder with the brown wires, and there is no fuse in it, then you can get a fuse at any auto parts store.

I'm afraid I don't know exactly where to look for the A/C fuse on a right-hand drive car, it must be somewhere under the trunk lining, probably on the LEFT side of the fresh air inlet box. Come on, owners of RHD 348's - help him out!

 

The green fuse in your last picture APPEARS to be the famous "hidden fuse", and it appears to be OK, but you'd need to check it with a voltmeter or a test light to be sure.

Your first picture in the previous post appears to be the wires going to the electric pump or the control valve for the heater system, and there is obviously a problem there. You need to cut out that red/orange connector and splice in something new that has a good, secure electrical contact. I personally haven't seen one melt there, but wherever there is excessive resistance you get heat, and that's what happens.

Have you pulled the center console to check the condition of the wires on the back of the climate control ECU? It's very easy.

 

Majin_JT

r u lyk txing dis w/ cell phone?

PS: where are you located?

 

Doesn't that burning area kinda concern/scare you? I would think your solution at the least is good advice, but having a burn like that with his observation is pointing to a greater problem.

rik

 

I think the writing is a little off maybe because he is from Yurrup. No problem though. I had my A/C blower fuse melt into the fuse block when I first got my 348. The mechanic rewired the entire blower to avoid all the relays that are in that circuit that tend to create resistance and therefore heat. He wired it using 8 gauge wire IIRC and put a self resetting breaker instead of using a blade fuse. Good luck in the fix, I'd bet you have a bad contact area on the control unit itself, or some bad connection by that floating fuse that looks like it has been worked on with some crimpers.

someone fixed a similar problem here:

http://www.ferrarichat.com/forum/showthread.php?t=178507&highlight=348+hidden+fuse
The fix was...

BT

 

unfortunately I'm not anywhere near great help on this, and my '348' is in a Mondial T so the block is different. BUT a lot of great guys here can help on your 348.

I'm going to monitor.

AND congrats on your purchase. BTW, the Queen's Royal carriage driver [one of two] owns a 348 also.

Rik