Amp Question

[Mytwojeeps2020]

The in-line fuse between my starter switch and the flasher has blown. It’s an old glass fuse, and the amp # is entirely obliterated. It looks like it may say “10”, but it that’s the case, isn’t that too high an amp fuse to place on that line?

Thanks!

BTW, I’m planning to get rid of the tubular fuse holder and replace it with this (photo).

[oldtime]

If your fuse holder will allow you should be running a 14 SFE buss or littlefuse.

[Rus Curtis]

The in-line fuse between my starter switch and the flasher has blown. It’s an old glass fuse, and the amp # is entirely obliterated. It looks like it may say “10”, but it that’s the case, isn’t that too high an amp fuse to place on that line?

Thanks!

BTW, I’m planning to get rid of the tubular fuse holder and replace it with this (photo).

This is on your CJ5?

I see on the wiring diagram there's an in-line fuse after the ignition/starter switch but before the flasher.  Looking at the back of the electrical section of the early Service Manual (SM), I see a reference for Directional Signal Fuse as "SFE 14".  The late SM shows different fuses for the flashers and the turn signals (14 amp and 9 amp).

Ken's all over this.  I had to look up what SFE meant.  That's what they call the glass body cartridge fuses (defined as "Society of Fuse Engineers")...  Learn something new every  day...

In the past, when I had to replace those type, I'd look for the rating on the metal cap.  One will have it stamped.  Sometimes very faint - and a big magnifying glass will help. If that fails - go to the SM!

I cannot imagine a parts store not stocking these.  I got used to carrying a little container in the glove box of extra fuses - just in case. 

Now, if the fuse blew, it could've been old.  But there may also be a short that will blow the next one.  I like buying a couple or three for that reason.  If you put a replacement in and it works, fine.  But if it also blows, AFTER you find the problem you have another spare to make it work.

Those blade fuses should work if you stick to the same rating.

[Mytwojeeps2020]

Oldtime, thanks for your response. The “Society of Fuse Engineers?”  I’ll bet they have wild Vegas conventions! 

I guess I’m off to the parts store today and get some 14 amp glass fuses (which I had hoped to replace with a blade fuse, but I don’t have/can’t find 14 amp blade fuses) locally.

Hi, Rus!  Yes, it’s the CJ5. I should have specified that.

I did look through the SM (as well as the owners manual), but didn’t see the amp listed. Must have missed it (wouldn’t be the first time).

In looking at the burnt out glass fuse, I’d swear it says “10,” but again I may be wrong. If it was 10, that may explain the shorting-out problems I’m having to work through with my earlier post:

https://cj3apage.com/Forum/index.php?topic=5094.0

Anyway, I’ll start with getting a 14 amp fuse and go from there.

Thanks!

[oldtime]

As previously mentioned the technically correct SFE 14 may not fit your application without a proper fuse holder.
In the pic below you can see the physical length difference between an AGC 10 and the SFE 14.
If your set up to use blade fuses then I’ll bet one of the SFE guys would allow you to use a 15 amp blade fuse if you get him snookered at the Vegas convention.

Thanks

[Rus Curtis]

Oldtime, thanks for your response. The “Society of Fuse Engineers?”  I’ll bet they have wild Vegas conventions!

I guess I’m off to the parts store today and get some 14 amp glass fuses (which I had hoped to replace with a blade fuse, but I don’t have/can’t find 14 amp blade fuses) locally.

Hi, Rus!  Yes, it’s the CJ5. I should have specified that.

I did look through the SM (as well as the owners manual), but didn’t see the amp listed. Must have missed it (wouldn’t be the first time).

In looking at the burnt out glass fuse, I’d swear it says “10,” but again I may be wrong. If it was 10, that may explain the shorting-out problems I’m having to work through with my earlier post:

https://cj3apage.com/Forum/index.php?topic=5094.0

Anyway, I’ll start with getting a 14 amp fuse and go from there.

Thanks!

If your blown fuse DOES say 10, then yes - that would explain some stuff.  As I now understand the SFE fuses, they are all the same diameter but the lengths are different based on the amperage rating, i.e. low amp (shorter) high amp (longer).  Ken posts additional info that I uncovered while searching this.  AGC fuses seem to be all the same length but with different Amperage ratings.
 Again, I didn't know all this until after googling.  Both are used on vehicles.  The way it's explained is the SFE fuses were made different lengths to avoid getting the wrong amperage replacement.

As far as the SM is concerned, I have two:  SM-1002-R6 and SM-1046. 

The early SM, electrical is Sect. I and the info needed was hidden in para I-80.  ELECTRICAL SYSTEM SPECIFICATIONS.  Of course on the last page at the bottom.  I'm not sure if I would have initially picked up on what was printed without Ken's clarification in his post. 

That SM lists:

Fuse Data:                 6V             12V
Directional Signal....  SFE 14       SFE 9


After looking up what SFE meant, then I understood what I was looking at.  I would have preferred seeing "14 amp" but that's just me.

When I look at the later SM, the electrical section is H and at the back of that is, H-152.  ELECTRICAL SPECIFICATIONS.  Again, on the last page and at the bottom.  This later publication must have started catering to the less trained by offering more easily understood terminology.

This SM states:

FUSE DATA:                      F4 ENGINE
Directional Signals.......       9 Amp
4-way Flasher.............      14 Amp


I wouldn't be surprised that these jeeps in the later manual probably had the beginnings of a fuse box - explaining the 2 different fuses.  But, that led me back to the earlier SM to decipher the SFE thing. 

I'd never looked at that before since my jeep came without the turn signal.  New to me.


It's a journey.......

[oldtime]

The “SFE” basically implies that the fuse is specific to automotive useage; where as “AGC” is a general purpose application. I’m not familiar with how those early designations interchange to modern blade fuse useage.
The only two fused electrical components on any of the correctly wired early cj’s is for the signal switch and the heater controls. These both connect via automotive fuse holder to the ignition switch “acc” terminal.
Here you see some original fuse holders along with a quantity of Buss brand fuses.

[Mytwojeeps2020]

Thanks, OT & Rus!

I’m going to replace my blade fuse connector, that runs between the ignition switch and the flasher, with a glass 14 amp fuse and cylinder fuse holder. Probably better to use the 14 amp glass fuse rather than the 15 amp blade fuse, I’m guessing.

Once I get power restored to the rear lights; down the road I’m planning to install a fuse block (blade style) and power it from the acc screw on the ignition switch. From there I’ll run my cigar lighter, electric wiper, back-up lights, etc., which I haven’t installed yet.

Again, many thanks!