Ammeter/electrical system question

[WoodyHank]

SO I found out I do have an ammeter, figured out how to take the instrument panel off, and I've got the instructions on how to fix it, but I just happened to pull out my little 85 handbook and it opened a whole other can o'...see, my ammeter will move a tiny bit to the (-) if one of the windows or the rear window is rolled down, and will move a tiny bit to the (+) when I start Woody, but here's what the book says: "the electrical system should be checked whenever the pointer indicates...no charge for an unusual length of time". Well, Woody is almost always at zero charge. Everything works on him, windows, accessories, all that. And I had his battery and alternator tested. So any ideas on this? Maybe the ammeter is broken and needs to be fixed asap? Help! And I've just got to add, I feel like I'm becoming obsessed with my jeep...is this normal, relatively speaking?

[oddfire]

You should probably disable your ammeter altogether as soon as possible. Its a terrible design and the leading cause of roasted FSJeeps. The design has the TOTAL output of the alternator going through the ammeter at the dash. Throw in a little galvanic corrosion for the last 30 years and you have a car-b-q waiting to happen. To bypass, just move the lead from one terminal to the other so their both on the same stud. Disconnect batt first. Put in a voltmeter instead...................phil

[ September 29, 2003, 09:42 PM: Message edited by: oddfire ]

[Ed Jack]

yeah, I'd second that. You're right in that you should disable the ammeter. If you are concerned about the reading, use a real multimeter to check it, or have your mechanic check your electrical system.

A bad ammeter (or ammeter connections) certainly might give false readings.

[Bob Barry]

But as to the reading, it really is only reading the charge to the battery; once the battery is charged-up, it won't be charging any more, so it will read right around "0". When there is a big draw, especially at idle, the alternator isn't providing enough juice to power whatever it is you're operating, so it is drawing some current from the battery as well.

Think of it as a directional flow-meter, telling you how much electicity is flowing toward (charge) or away-from (discharge) the battery.

But as others have noted, BYPASS IT NOW! They all burn up, sooner or later. Even better is to create an additional direct charging-circuit from the alternator to the (+) stud on the starter relay (I used a 12" length of 4-gauge wire for this purpose), so the battery isn't being charged through your dash harness (as it is now, which is also why you shouldn't try to run the engine on a stock-wired FSJ in order to re-charge a dead battery).

[will e]

Why not put in a shunt? This would limit the amount of power going through the ammeter.

http://www.ifsja.org/ubb/ultimatebb....=021679#000000

[will e]

Originally posted by Bob Barry:
[QB]But as to the reading, it really is only reading the charge to the battery; once the battery is charged-up, it won't be charging any more, so it will read right around "0". When there is a big draw, especially at idle, the alternator isn't providing enough juice to power whatever it is you're operating, so it is drawing some current from the battery as well.

Think of it as a directional flow-meter, telling you how much electicity is flowing toward (charge) or away-from (discharge) the battery.

[QB]

Mine doesn't appear to work this way. If my meter is reading close to zero with the truck running and I turn on the A/C the meter goes positive to about th 15 or 20 amp mark. So mine appears to be showing total flow.

[Joe Guilbeau]

By moving the wires to the same post all you have done is remove the Ammeter from the circuit, this is good, but all of the amps from the alternator STILL run under the dash and back to the solenoid.

The Red supply 10 Gauge wire is just as bad as it was and the Yellow return 10 Gauge wire is just as bad as it was. As are the splices that run the horns, lights, fuse block ect...

In fact, nothing was done BUT remove the ammeter from the series circuit, so unless one acutally replaces the wires, little has been done other than protecting the Ammeter from harming the Jeep.

One could simply replace the ammeter with an upgraded design and keep an Amp Gauge and still be in the same place as putting both terminals on the same post of the existing ammeter. In addition, one also now has a working ammeter to boot.

The above advice is great, just don't forget that all of the wiring is old also, and nothing has been done to replace it.

[WoodyHank]

so short of replacing all of the wires in woody, which is just a little out of my budget, is there anything I can do to stop the carbque and make him safe enough for me to drive with my dogs to Montana?

[Bob Barry]

Well, after my in-dash almost-fire, I did two things that kept most of the amps out from under my dash:

* I run the headlights off a pair of relays, so the dash switch just triggers the relays that are fed from an extra fuse-block I added right off the alternator.

* I run a charging-wire from the charging stud on the back of the alternator to the starter relay on the passenger-fender. I used to have a 10-ga wire for that, but since adding the winch, I moved to a 4-ga wire. I relocated the original red charging-wire from the stud to the starter-relay so that, in the unusual circumstance that the 4-ga charging-wire burns up, the sensing wire to the plug on the alternator will realize it's been cut-off and stop the alternator from charging.

* The other thing you could do is use corrugated split-loom tubing and zip-ties to keep all your wires under the hood up out of harms way. They regularly melt and short-out against the exhaust manifolds and the exhaust-crossover on the intake.

[WoodyHank]

Well, I did what any good FSJ owner would do when confronted with a life-or-death-barbque-behind-the-wheel situation. I went and took a bubble bath, shaved my legs, and had a glass of wine (sorry guys, I'm a girl), then after that, I read these posts, threw on some clothes and went to take a look at woody's innards.

Looks like there's been some electrical work done on him--the split-looming/zip tie scenario you described Bob has been done. And there's a switch that says Auxillary and Main (???) and it's connected to various other groups of wires. There's also a brown/green/white/yellow grouping that's been wholly disconnected on one end. Beats me. I know that the First owner took perfect care of Woody,wrote down car washes, loved the jeep (license plates: SeaLion), maybe had the work done. Second owner, still trying to get the records from her via the Third Owner who is a total ditz (at a minimum). I'm going to try to get some pictures posted so you can see the damage, and thanks, and please bear with me guys. I know I'm pretty ignorant about all these things, but I love my jeep, I'm not selling him, I may not be able to get him all fixed at once, I may not be able to take him to Montana with us, but he's getting fixed as I have the money, and he isn't going to roast in the meantime. So thanks for being patient with me, I really am trying to learn [img]smile.gif[/img]

[mtn goat]

WoodyHank, You can literally spend hundreds of dollers doing everything people on this board have done. (relays and such) but, the simple act of bypassing the ammeter will GREATLY reduce the chance for a fire. Its like anything, the more you do, the less likely you are to have a problem. most people hear just take the fat red wire off the back of the ammeter and put it on the same side as the fat yellow one, then tighten them down together. (you should clean the ends with some sandpaper when you do this). Yes, you still have all the amps going under the dash...but you have GEATLY decreased the potential for a fire....and it was quick and free!!! But, the meter no longer works...(does anyone even look at those stupid things anyway?)

now, to take that a step further go out and get a nice fat wire and hook it from the output on the alternater to the starter relay like others have suggested, you have decreased the possability of fire even more...and only cost the $5 for a wire and ends. At this point I would say you are as safe as any other car on the road...could you still have a fire, well, yes...but so do brand new trucks.

Now, you could start adding extra fuse boxes and relays and go whole hog, this further decreases your chances at fire. but at some point the work doesnt give you the gains. Great for those that do, I will in the future too, but what is reasonable to be safe? at a minimum I would hook the two ammeter wires together and just forget what the guage says. (mine works the same way yours does by the way) The problem comes when corrosion build up on the terminals or inside the ammeter itself. corrosion will act as resistance and get HOT...if it gets hot enough it will burn. by putting the wires together, you drop contact connections from two...down to one, so only half of the resistance can be there and hence, half the heat.

wille, I think your A/C is pulling some serious amps! check for grounding on that bad boy...

[ September 30, 2003, 12:41 AM: Message edited by: mtn goat ]

[Bob Barry]

I second Mountain-Goat's observation.

The alternator bypass is free.

The shorter charging-circuit is cheap.

The relays and connectors to power the headlights is under $20, plus some soldering.

But if you've got wires disconnected under the hood, and there are mystery-switches under there as well, you've got to determine WHAT the heck is going on, and restore it to at least as good as it was when new. Botched wiring by previous owners is another major cause of fires.

We'll help walk you through figuring out what's going on, and it will just make you love the Jeep even more.

I would also recommend you think about doing the soldering yourself. It's not difficult, but it is rather empowering to be confident that you can repair any wiring problems ten-times better than a "professional" at a garage could.

We know what wires should be there, where they should run, and what might be a likely problem with them. We'd be glad to walk you through fixing those wires and getting your beauty back on the road safely. [img]smile.gif[/img]

[79_Limited]

now, to take that a step further go out and get a nice fat wire and hook it from the output on the alternater to the starter relay like others have suggested, you have decreased the possability of fire even more...and only cost the $5 for a wire and ends. At this point I would say you are as safe as any other car on the road...could you still have a fire, well, yes...but so do brand new trucks.

I had my ammenter bypassed. I did not do it myself but am going to check and see if it was bypassed correctly.

As for hooking the wire from the alternator to the starter relay do you just splice the wire into the output with the other wires? Where do you connect the other end of the wire on the starter relay?

[will e]

Originally posted by mtn goat:
wille, I think your A/C is pulling some serious amps! check for grounding on that bad boy...

Well it is really warm here. Will that make a difference???

Seriously. My guage may be off, I am not sure exactly how many amps are being pulled. The A/C fuse is a 25 amp so they expected a pretty good amount of draw. My understanding is the fan motor at high is good for about 5 to 7 amps and the A/C clutch is good for about the same.

[Bob Barry]

Originally posted by yumyum:
As for hooking the wire from the alternator to the starter relay do you just splice the wire into the output with the other wires? Where do you connect the other end of the wire on the starter relay?

No. You take the red wire that currently runs to the alternator, cut off the old ring-terminal, crimp and solder on a larger ring-terminal (with a length of 14-ga fusible-link, if there isn't already one on there), and bolt that to the (+) terminal on the starter relay.

Then you run a heavy-gauge cable from that stud on the back of the alternator to the same (+) terminal on the starter relay (the one the (+) battery cable runs to). I used a length of 4-ga cable with copper lug ends that I crimped and soldered on myself. You might be able to find a pre-made length of cable with the right terminal-ends- just make sure it doesn't run anywhere near the exhaust manifold, and that it doesn't chafe on any metal.

The reason for relocating the original charging wire to the starter relay is so that the regulator in the alternator cuts off if the new heavy-gauge charging cable burns itself up.