Electrical Gremlins

First, I'll start off by saying that people should do as I say, not as I do.

I've always told 330 GT (and other Ferrari's of that era) owners that they should remove each ceramic fuse, clean the ends and the contacts annually.  I think that will solve or prevent about 90% of the electrical problems, once your electrical system is well sorted out.

That said, the last few times I've driven the 330, I've noticed that the gauges stopped working part way through the drive.  Those in themselves aren't too critical, however, the same fuse supplies power to the cooling fans.  So if you are in stop and go traffic, the car is likely to overheat and with the gauges dead, it probably won't be obvious until you see steam from the engine area.

After I got back this time, I pulled the car into the shop and after it cooled, moved the washer bag and removed the fuse box cover.  In looking at that particular fuse, it was in questionable shape, looking like it had been hot enough to deform the fuse bar, but not enough to melt it.  This is a blue fuse, originally 30 amp, but the only available replacement is a 25 amp one commonly used on old VW bugs.  So it is already at its capacity and I've added a helper fan on the rear on the radiator.  I think that the corrosion on the fuse ends and contacts would allow the gauges to work when the car first started, but when the fans came on to cool the engine, the corrosion was too much to power the load.  Anyway, I cleaned and swapped that fuse with another 25 amp one.  The gauges then worked fine.

The next day, I took the car to a local show and on the way home, the turn signals no longer worked.  I can remember them working when I first left home.  Needless to say, I hadn't pulled and cleaned each fuse as I preach!  So again, I moved the washer bag and took off the cover.  It turns out that the fuse location I swapped with was for the turn signals.  So that fuse (bottom one above) is flaky and I replaced it.

When you remove the fuses, keep them in order.  The 8 fuse 330 GT covers have the amperage shown, but earlier covers don't.  These ceramic fuses are problematic.  You can see the one fuse at the top middle which broke simply from removing it from the contacts.  Buss used to make this style of fuses in glass with conical stainless steel ends, but I haven't seen them for a while.  In fact, the ceramic fuses are hard to find.  I went to a VW dealer and was told that they don't stock them anymore.  They recommended a VW repair shop and they had them.

   

I find that a scuff pad works well to clean the fuses.  I use a Dremel with a worn wire wheel for the contacts.

   

When I put the fuses back, I always position them so the fuse wire is facing up at an angle.  That way, it is easier to see if one is melted.  It's been my experience that electrical problems seem to occur at night when it is raining and the flashlight batteries are dead.  So if you are using your cell phone screen for light, the more help you have, the better.

My last suggestion is to put rubber washers under the knurled nuts that hold the fuse box cover on.  The rubber allows the nut to be finger tight without the worry of it vibrating off.  I also do the same for the air cleaner knurled nuts.

Note, when on the road, a simple quick fix is just to twist the fuse back and forth a couple of times.  This usually cleans the fuse and contacts enough to get things working for a while.  But in the long run, you need to do a thorough cleaning.

There are a couple of other weak points in the 330 fuse box.  The fuse contacts are just copper and are riveted to the Bakelite holder.  I've seen the rivets get worn so the contact isn't making good contact with the spade connectors, thus causing intermittent problems.  The solution there is to solder the contact base and spade connectors to the rivet.  The contacts themselves act as springs to hold the ceramic fuse between them.  If they get pushed out too far, they won't make good contact with the fuse end.  So I always make sure that both contacts are bent towards the center and need to get pushed out to insert the fuse.  I've seen other owners use O-rings over the contact ends to hold them tight on the fuse.  Not too good looking, but then they are well hidden, under two covers with the washer bag in the way.

There was a fallout of cleaning all of the fuses.  A couple of days ago, I drove the 330 to a volunteer gig.  First I noticed that the turn signals were no longer working  Later I noticed that the ammeter was on the discharge side.  Now, the two of these shouldn't be related as they are fed by separate fuses.  Anyway, today I moved the washer bag and took off the fuse panel cover and fuse block covers.  At first glance, I saw that the regulator fuse was blown, so I replaced it and wiggled the turn signal fuse.  The turn signals then started working, but when I started the car, the regulator fuse blew again.  In the process of isolating the blown fuse problem, I saw that the turn signals were no longer working.  It turn out someone (me!) plugged the turn signal wiring into the regulator fuse.  This would have happened in '89 when I was first putting the car together.  Either I didn't read the little black and white wiring diagram in the service manual, or I just did it wrong.  Then when I looked at the fuse it was supposed to be connected to, all four spade lugs were in use.  The color wiring diagram I've since made only shows four wires for that fuse, so one of them was also in the wrong place.  After some more tracing and testing, I found that the extra wire went to the cigarette lighter.  It belonged on a fuse not controlled by the ignition switch.  Now, I might have moved this so I could keep a radar detector plugged into the lighter and not have to turn it off all of the time.  I have put in a switched hard wire for the detector, so I put the cigarette lighter wire back where it belonged, freeing up a lug for the turn signal wire to be in the right place.

As to why the regulator fuse kept blowing, I can only surmise that I had a 'strong' 8 amp fuse there.  In the process of cleaning all of the fuses, they all were mixed up and didn't necessarily go back in the same place.  So the fuse for the regulator could have been replaced with a normal 8 amp fuse and the turn signal draw in conjunction with the regulator was just enough to blow it.  At least now, the car runs without blowing a fuse and the turn signals also work.

It turns out that any 8 amp fuse eventually blows, though it took several minutes of driving.  I ended up fixing the voltage regulator.

As mentioned above, one problem is worn rivets in the fuse block.  Over the years, I've noticed that the instruments would stop working periodically.  Those by themselves aren't that critical, but the same fuse also supplies the radiator fans, so the car might overheat in stop and go driving.  Of course without the water temperature gauge working, the first indication would be some steam as the radiator cap let off excess pressure.  Each time this happened, I would just twist the fuse and perhaps bend the contacts a little toward the center.  This solved the problem for a while as it would put pressure on the rivet and restore electrical contact.  The last time this happened, I took a careful look and saw that the rivet was loose and the fuse contact could wiggle around.  As you can see by the picture, the contact has gotten hot and turned color.  This would have been caused by the heat being generated by the bad contact.  This particular fuse has a bus bar on the inside providing power when the ignition switch is on.  There is a rivet through that bar to the outside where there is a spade lug and the fuse contact. It is a 30 amp fuse due to the load of the fans, thus any poor contact will heat up.

   

As you can see in the right picture, the Bakelite is cracked and that probably contributed to the looseness.  I used a pair of needle nose Vise-Grip pliers to re-squish the rivet.  Then I cleaned both sides and soldered all of the components together.

 

Hopefully, between the better mechanical connection along with the solder, I won't have any future failures with this fuse.  I did check all of the other contacts and this was the only loose one.