Fuse box melt prevention?

[Marty Rogan]

I agree with you on that one. It seems like if they were all soldered together, how could you maintain varying fuse levels on different circuits?

Marty

[Inf]

Yes, the diagram on the site did not make much logical sense. I planned on (if I decided to do that) just bridging the existing connections.

Andrew

[N5572B]

Solering one side makes better connections on that side. If you read the site, he stated if you soldred BOTH sides you would loose the individual fusing capability. The side he suggests soldering is the input side of the fuse box and therefore does not need to be separate. I think he put a lot of thought into the issue. Also, he is showing the bottom of the fuse box, solder on the passenger or input side. Makes perfect sense and is ONE way to help the issue of overheating fuse boxes...IMHO.

Dave

71 240 project with a majorly cooked fuse box...

[EScanlon]

Sorry Dave, but your theory won't wash. This is exactly the type of problem that Alan H. rallies against, the A$$umption that because you read it on the internet it makes it not only TRUE, but irrefutable. In this case, the author has done some "fixing" but I would love to find out if this really did in fact eliminate his problems, and not cause a whole new series of them.

Look at the schematic for the 240, and if you go to the "one side" theory, what you'll discover is that you will be joining circuits that are NOT designed to be joined. The 240Z fuse box has TWO columns of fuses not one. Go ahead, try to decide which passenger side he was referring to.

Next, if you look at the little drawing showing which side to solder, you'll note that he refers to only soldering one side of the fuse box, and his diagram shows 6 fuses. Now I'm not sure if he's referring to a 240Z or a SRL/SPL vehicle, but MY Z has 10 fuses, and my SRL 311 has 6. His connections, all on the one side of the fuse box do eventually connect on the SRL311 wiring diagram but NOT on the 240Z's.

On the Z, the least you'll do is have your fuel pump, accessory relay and resistor and tach contstantly "live", as well as the headlights. EVEN WITH THE IGNITION OFF. That is if you connect the wires on the one side. If you connect them on the other, then you'll REALLY cause heck.

On the 240 Z wiring diagram, look SPECIFICALLY at the bottom side of the fuse box drawn. You'll note a Blue/Red Wire and a Black/White all the way to the right hand side of the bottom edge. Those are SWITCHED via the Ignition and Headlight Switches and only when those switches are turned ON. Join those wires to the White/Red to the left of the fuse box, and you will have defeated the switches, as well as connected the Positive side of the battery directly to the output side of the Alternator and Voltage Regulator. Sounds Yummy doesn't it?

So have at it, and watch your system FRY! Or be beset with the thousand and one "mysterious" electrical problems that beset the 240Z's due to half-a$$ed attempts at "fixing".

So, IMNSHO, this is a B A D idea.

Enrique Scanlon

[EScanlon]

Now, the reason I posted the above so strongly is that one very important note must be made:

THE FUSE BOX IN Inf's GALLERY DOES NOT MATCH THE ONE IN SPORTS Z MAGAZINE.

The one in Sports Z Magazine is a different style, in that the whole passenger side does indeed have a brass bar connecting the input side of all those fuses. Soldering that side would be a good idea IN ADDITION to tightening the crimps. Only two White wires connect to that side. Read the article if you have doubts.

But if you look at Inf's you'll right away note the difference on the passenger side. Inf's has a White/Red wire on the bottom with a rubber cap hiding the bolt/nut and a Red wire which connects to the Headlights. Shunt here and your lights stay on all the time.

Enrique Scanlon

[louisf]

What do you do if a fuse holder has a broken arm. Do I by pass that wire with an in linee fuse or do they sell fuse holders. My box isnt fried so I would like to just fix the holder.

[Inf]

I thoroughly sanded out the inside surfaces of the mounting clips last night, and I am thinking that it will eventually tarnish/corrode to the point of melting again. Aren't there some chemicals that I could spray on to coat the points that will both protect it from corrosion as well as improve the connection?

EScanlon: Do you think there is there any effective/simple way to clean the film off the back of the brass strips/rivets that you mentioned? Some of the soldering irons I have used in the past had adjustable temperatures via a rheostat, and maybe on the lowest setting I would have a lower risk of melting the plastic. I have done a lot of soldering before on those cheap generic circuit boards and I think as long as the solder will bond to it easily (as in nothing preventing a good hold, like that film) I should be able to do it safely.

Andrew

[tanny]

I know there are certain greases that can be applied to light bulbs that will prevent oxidation. I would think that they would work on fuses also.

[EScanlon]

In the article in Sports Z Magazine's last issue that has been cited previously and by myself above, Joe Demers makes note of this dielectric grease.

His statement is that in HIGH Voltage LOW current applications, the dielectric grease does not cause problems. However, in HIGH Current situations, regardless of voltage, he recommends against it.

Joe points out that dielectric grease is NON-conductive, but effective in preventing corrosion.

What he recommends for the crimped connections is soldering and to be covered with some form of RTV (Room Temperature Vulcanizing) coating or Shrink-Wrap tubing.

As far as how to clean that film off the back, you could grind, sand, sandblast or, since you're considering soldering at least the crimped joint, why not remove the joint from the fuse box, and use a good quality Rosin Core Solder. As long as you can get the metal hot enough the rosin usually has enough acid in it to bite through most coatings.

2¢

[Bambikiller240]

Originally posted by EScanlon

In the article in Sports Z Magazine's last issue that has been cited previously and by myself above, Joe Demers makes note of this dielectric grease.

His statement is that in HIGH Voltage LOW current applications, the dielectric grease does not cause problems. However, in HIGH Current situations, regardless of voltage, he recommends against it.

Joe points out that dielectric grease is NON-conductive, but effective in preventing corrosion.

What he recommends for the crimped connections is soldering and to be covered with some form of RTV (Room Temperature Vulcanizing) coating or Shrink-Wrap tubing.

As far as how to clean that film off the back, you could grind, sand, sandblast or, since you're considering soldering at least the crimped joint, why not remove the joint from the fuse box, and use a good quality Rosin Core Solder. As long as you can get the metal hot enough the rosin usually has enough acid in it to bite through most coatings.

2¢

Enrique: Aren't these connections rivited into the plastic box? Are you saying to drill out the rivits, and then solder? How would you reinstall the connector into the plastic securely? Maybe a dumb question, but I don't have a fuse box to examine without disassembling my console.

Carl

[24OZ]

Hi Andrew and everyone else on here,

here is a good write up, with good pics of the problem, including a link to some solutions.

MElt DOwn ..........

[EScanlon]

Carl:

In all honesty, I did not disassembly my fuse box and do the solder technique. I tried but felt that the heat was going to exceed the melting point of the plastic and I just gave up.

What I did do, was to use a punch and small anvil to smash down the rivets tighter, and I did that without removing the fuse holders from the fuse box itself. I believe that you can remove them from the fuse box simply by pushing in the two little tabs that stick out on each side of the fuse holder, but I'll admit that I'm going off memory and it's been months since I had the fuse box open and was working on it.

Then I gave the back of the fuse box a shot with some clear Plasti-Kote in a spray can. Just enough to put a thin film of "plastic" to protect from the elements.

I also replaced the headlights with the new Zenon tubes (Not the high wattage ones) and have been extremely pleased with the results.

But now you got me thinking, and I'll have to get out there and check.

Enrique Scanlon