Tom, so how does the ammeter perform now? During starting, headlights, charging, etc.
Ammeter/fusible-links ......late model 40-series (1 Viewer)
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Tom, so how does the ammeter perform now? During starting, headlights, charging, etc.
matt.mcinnes
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(And sheep jokes aren't welcome in my threads Charlie ..)
No they take there sheep very seriously
4WD Toyota Owner Magazine
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Fantastic writeup! Quick question: in your pic of the fusible link, there us a white wire with blue stripe. Can you tell me what that handles in the electrical system? Thank you!
Dave
Dave
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- #25
Hi there.
It doesn't perform at all really (which is what I've been used to seeing for almost all of the last 30 years). The biggest movement I get is a "microscopic twitch" when I have my hazards on.
In my opinion, if I was to deliberately downsize the "monitored fusible link" to obtain a "functioning/useful ammeter" ... then my cruiser would become unreliable because that fusible link would be at risk of "blowing" under peak loads or when it has suffered minor-deterioration from corrosion/fatigue some time in the future. And probably more importantly - if I downsized that fusible link enough to make my ammeter work properly - I think it would also be dropping the voltage to downsrtream components to unacceptably low levels (causing further "unreliability problems" and damage). Edit: My fear of "dropping voltage to unacceptably low levels" (expressed here) proved to be unfounded when I bench tested a similar ammeter (later in this thread) to reveal that only 0.3V of voltage drop in the fusible link produces a full-scale ammeter-needle-deflection. (However I'm still not prepared to downsize my fusible link.)
In other words ... I think the design of the late-model ammeter system is basically flawed and these ammeters serve no useful purpose.
In fact, I'm almost tempted to fit a "charge light" (but I won't because I prefer to keep my dash looking standard).
That's the wire that goes to the ammeter.
Great write up!
Yep
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John McVicker
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Really like your write ups...very informative.
John
John
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- #27
Thanks John ... Sometimes I think I write way too much...So I'm glad it's appreciated by some.
Thanks for another great write up!
I've been looking for a source of the larger brass connectors like the ones used in the fusible links for a few years. At one time Wrangler Power products carried the big silver ones in the pic below but they're a little large (and not corrosion-resistant brass). They were bought out by a company in Portland Oregon and no longer sell supplies. If anyone knows a source please post it up.
I've been looking for a source of the larger brass connectors like the ones used in the fusible links for a few years. At one time Wrangler Power products carried the big silver ones in the pic below but they're a little large (and not corrosion-resistant brass). They were bought out by a company in Portland Oregon and no longer sell supplies. If anyone knows a source please post it up.
Based on this thread it looks like the factory ammeter is a lost cause. I was having a lazy Saturday afternoon and decided to do this.
I know others have done the same before. It didn't cost me anything. The PO had a VDO voltmeter mounted under the dash. I took that unit apart and adapted it to the factory cluster. I saved the ammeter so it's completely reversible. But I can't ever see going back. The factory wiring is missing at the batter/fusible link on my truck.
I know others have done the same before. It didn't cost me anything. The PO had a VDO voltmeter mounted under the dash. I took that unit apart and adapted it to the factory cluster. I saved the ammeter so it's completely reversible. But I can't ever see going back. The factory wiring is missing at the batter/fusible link on my truck.
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- #30
Wow! Both goodlooking and functional!
It looks like its supposed to be there!
It looks like its supposed to be there!
What size is that voltmeter dkroth? I'd like to do something similar as the ammeters in my 45 and 47 are useless IMO.
It is/was a 2" (2 1/8" ??).
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- #33
Just looked into sourcing these 8mm spades (male and female)myself because I always like to be prepared for any eventuality and I wasn't really happy with the way I reused the old spades in this thread.
(One day I may actually remake my fusible links using the new spades I've just successfully sourced.)
And you are right Numby! They are definitely hard to locate. (Took me about 1 1/2 hours of Internet searching.)
Anyway here's what I got:
I used a supplier called "Auto Electrical Solutions" on Australian eBay:
CRIMP TERMINALS FEMALE SPADE 8MM RECEPTACLE 10 PACK - eBay, Other, Car Parts, Accessories, Cars, Bikes, Boats. (end time 11-Jul-10 21:57:10 AEST)
No problem if you live in Australia but this store is setup to be rather unfriendly to anyone living outside (and even to a close neighbour like me in New Zealand who should be being treated like a fellow-Australian for heavens sake
).But that isn't a problem because the owner (Rick) is actually a kiwi (born in Auckland).
So if anyone is interested in buying off him who lives outside Australia - just PM me. And if you do so over the next few weeks (while I still have his contact details) ....I'm sure he wouldn't mind me helping you get in touch with him for a "supply&shipping quote" (provided you can clearly list what you want to buy from his on-line store).
PS. There's nothing in it for me .... I'm just trying to help others source difficult-to-find parts.
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- #34
Sequel
I was very tempted to follow Dkroth's lead and convert my useless ammeter to a voltmeter. (That's such a nice job!)
However I need to have an air pressure gauge with my future ARB diff locks. So I've decided to combine the two.
This is the result:
Ignore the 3 coils of wire tucked under the dash. ... They will eventually go to 2 diff lock solenoids and an aircompressor solenoid/relay.
(And the little red and green LED lights and chrome switches are for the diff lock stuff too.)
So I'll now be able to rest easy on all my long-distance night-time driving (provided the voltmeter shows good charging voltage all the time - which I'm sure it will).
In the past I've often worried that perhaps my alternator may have secretly "shat itself" while I'm driving ... and that therefore I won't be able to restart next morning.
I was very tempted to follow Dkroth's lead and convert my useless ammeter to a voltmeter. (That's such a nice job!)
However I need to have an air pressure gauge with my future ARB diff locks. So I've decided to combine the two.
This is the result:
Ignore the 3 coils of wire tucked under the dash. ... They will eventually go to 2 diff lock solenoids and an aircompressor solenoid/relay.
(And the little red and green LED lights and chrome switches are for the diff lock stuff too.)
So I'll now be able to rest easy on all my long-distance night-time driving (provided the voltmeter shows good charging voltage all the time - which I'm sure it will).
In the past I've often worried that perhaps my alternator may have secretly "shat itself" while I'm driving ... and that therefore I won't be able to restart next morning.
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- #35
Only one problem - The backlighting in the voltmeter is way too bright for my liking!
It makes the combination meter lights look so dim. But in fact they're NOT! They're now the ideal brightness (after I swapped in LED bulbs).
Dash lights should not be "distractingly bright" in my opinion.
I guess I'll live with it though (rather than try and dim it) because at least the voltmeter is obscured from my view by the steering wheel unless I either:
It makes the combination meter lights look so dim. But in fact they're NOT! They're now the ideal brightness (after I swapped in LED bulbs).
Dash lights should not be "distractingly bright" in my opinion.
I guess I'll live with it though (rather than try and dim it) because at least the voltmeter is obscured from my view by the steering wheel unless I either:
- lean forward slightly, or
- turn the wheel for a corner.
I'm going to ask what is probably a stupid question- but here goes: Could the late model ammeter be made to be more sensitive by running 2 smaller size fusible links in place of the one and connecting the Ammeter across only one of the wires?
I just bought a new one because the old one melted (why???) Have yet to check the fuses and that of course will be the first thing I do before installation.
I also wanted to add that I have found soldered connections at a spade terminal to be more prone to fraying with vibration/ handling. Not that it should not be soldered- in fact I think your solution is perfect.
Pete
I just bought a new one because the old one melted (why???) Have yet to check the fuses and that of course will be the first thing I do before installation.
I also wanted to add that I have found soldered connections at a spade terminal to be more prone to fraying with vibration/ handling. Not that it should not be soldered- in fact I think your solution is perfect.
Pete
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- #37
Hi Pete.
Ya wanna know about "stupid"! .....I've just been fitting new engine mounts and my workshop happens to be "my sloping driveway". Anyway, I had a devil of a job getting the damn things to line up properly.....that is....untill I realised the propeller-shaft-mounted handbrake was the culprit. (Chokking the wheels and releasing the handbrake instantly stopped the engine-transmission from winding-up/twisting and allowed the mounts to line up easily!!!.... But you wouldn't believe how long it took me to figure this out.
Anyway --to your question. I thought of running two fusible links there but the only way I believe it would work would be to install a switch as well. You could then "open" it to take one out of the circuit so ALL the current flows though the other "small-gauge monitored link" whenever you want to see whether your battery is charging or discharging. (But having both links in the circuit during normal operation would keep the electrics reliable.)
However I thought the voltmeter was a simpler and better solution for me. It gives a useful readout all the time while my key is in the "motor-run" position.
I don't think you'll find anything from checking your fuse block because the fusible links protect wiring that isn't protected by the fuses in that fuseblock. (If you have access to a wiring schematic you can see which wires these are.)
Common causes of a fusible link blowing are:
- Loose wiring touching exhaust piping
- spanner touching a live terminal
- ignition switch damage/shorts
- etc
Tom
I've been pondering this for a bit- but being as dense as I am- I can't see the need for the switch. Wouldn't the ammeter still measure the flow across just one wire without cutting off the current passing thru the other?
And also it was not the fusible link that melted on my truck but the actual ammeter itself. That is why I need to check the fuses and diagnose the cause before I just plop in replacement.
Just out of curiosity do you think the deterioration of your fusible link would have been noticed with just a voltmeter? I'd guess that you would have still gotten a solid read there and so it seems to me that in this case the ammeter actually was the preferred gauge to have. Of course both is the best is it not?
And also it was not the fusible link that melted on my truck but the actual ammeter itself. That is why I need to check the fuses and diagnose the cause before I just plop in replacement.
Just out of curiosity do you think the deterioration of your fusible link would have been noticed with just a voltmeter? I'd guess that you would have still gotten a solid read there and so it seems to me that in this case the ammeter actually was the preferred gauge to have. Of course both is the best is it not?
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- #39
IMO ...The best way of looking at it is ......"In a late-model 40-series like mine the ammeter is really a voltmeter that has been calibrated in amperes (current units)."
So it is measuring the voltage-drop across the fusible link through which charging/discharging current passes.
The only way to get enough voltage drop to cause decent needle-swings is to have the FULL charging/discharging current flowing through the monitored fusible link.
(Hope this explains it better.)
Ah .... So you were referring to these fuses ijn your engine bay (and not the ones in your fuseblock inside the cab as I had mistakenly assumed):
Quite right to check them! They should be only "5A rating" and if someone has fitted oversized ones that would certainbly account for your ammeter failure.
PS. Early 40-series didn't use this arrangement (I'm describing) for the ammeter. I think the change occured in 1978?
No. I don't think the voltmeter would have revealed that fault. So having both an ammeter and voltmeter now is extra-good.
You make the meter more sensitive by increasing the shunt resistance. Doubling its length doubles its resistance and doubles the sensitivity of the meter.
