FJ40 AMP gauge test
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Hi Pin_Head, I checked the small black plastic fuse holder with the two fuses. Both are in working order. I did look a little more closer at the needle on the gauge and noticed that if I put a load on as head lights, I can see the gauge move ever so slightly. So it looks as power is going to the gauge (checked with test light also). Would the gauge be failing with this kind of movement?
Thanks
Thanks
No. It is normal operation if the charging system and battery are in good shape and everything is working properly. If you want to see it work, disconnect the coil center wire temporarily and crank the engine for 1 minute to discharge the battery and then start it up. It will deflect to the right as it charges the battery.
Cool! I checked in my holder and the fuses were blown. What value should I replace them with? No wonder my gauge didn't seem to work.
Drew. - Can you please post photo(s) of your fuse holder so I know what it looks like and where it is located?
I don't think I have one of those "fuse holders" on my vehicle and your photo(s) would help me to confirm this.
Sorry for the hijack (but I'm from downunder and ya gotta make allowances for that)
Noproblemmo
Thanks heaps Drew.
I've owned this cruiser for 27 years and I've only now found out that I have those fuses too!
Your photos were just what I needed.
My fuse holder was hidden beneath a whole load of electrical tape. Once I had the tape off, I found the fuses were okay (not blown).
I guess my ammeter needle doesn't move much because I always keep my big battery in good nick and automatically replace it after a set time - even if it still checks out alright.
Can't you read your fuse ratings off the metal ends of the fuses themselves? (They are usually stamped there.)
I you can't read yours - then give us a yell and perhaps I can read mine.
PS. The wiring diagram in my manual says my ammeter fuses are each of 5A rating.
Its alive, I replaced my fuses and saw the needle move for the first time ever! Thanks all!!
and thanks to you I found that my BJ40 has those fuses too Drew. (Previously I had thought that perhaps my BJ40 was different and didn't have them!)
Is there a shunt in your system (not short)?
For some reason all my power from the alt runs through the amp gauge then to the fuse block.
For some reason all my power from the alt runs through the amp gauge then to the fuse block.
and thanks to you I found that my BJ40 has those fuses too Drew. (Previously I had thought that perhaps my BJ40 was different and didn't have them!)
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I get jealous every time I see your engine Tom. Did you relocate your fuel filter or has it always been on the battery tray?
Well there's no way 5A fuses would be carrying the actual charge/dischage current so I believe the ammeter must effectively be "shunted" Tankota.
My alternator is just the "stock" one and I think even this little thing puts out 35 amps (as I recall).
Here's a section of the wiring diagram - but I haven't had time to study it to work out exactly where the shunting occurs:
I moved it there so I could fit the deeper filter cartridges that are both cheaper and more-readily-available in this part of the world.
On the intake manifold the area underneath the holder was too restricted.
On '79 and up, the fusible link serves as an external shunt. On earlier cruisers, all the current passes through the meter in the dash, which has an internal shunt. When the fusible link shunt blows or gets corroded, the fuses blow to protect the meter.
Thanks Pin_head. That sort of talk went "over my head" before. But no longer. Thanks to MUD I think I've developed a much better understanding of the ammeter setup now.
Perhaps yours is broken or you are not familiar with how they work?
When everything is normal and the truck is running the needle points straight up at zero, indicating that the battery if fully charged and the alternator is supplying all the chassis power.
To test it, just turn on all the lights and honk the horn. The needle should deflect to the left, indicating the power drain from the battery. Once you start the engine, it should deflect right as the battery charges and then return to zero.
i will test, but even after having to charge my battery because they were dead i never seen it move....well i mean 1/64 of a inch, barely noticable, a motion that could be associated to vibration of the engine running, not sure.
Hmm, well then maybe I'm not sure mine is working. I did just what you said and observed little, if any, movement. When I started the engine, if I revved it up I saw a little rightward deflection like eleblanc described, but very little.... Checked the fuses and they're ok. Maybe the link is shorted?