The Stovebolt Site Forums The Shop Area The Electrical Bay PEGGED AMMETER NEEDLE

I wanted to clean up my wiriing under my dash because it was a rats nest under there. Removed the complete round dash cluster with the ammeter in it.
Clean it all up and reinstalled the cluster and now find my ammeter is pegged to the charge mark....This truck was converted to 12V at some point.
I am running an under dash after market voltmeter and previous to my removing the cluster the needle reading on the ammmeter was centered midway between the D & C.
The under dash volt meter works as it should,
I undid the neg side of the battery to see it the needle would center again but it is still pegged with out the battery hooked up.
I am assuming that the gage is fried due to me hooking up the ammeter to the 12V system when the gage is for a 6V system.
There is no Runtz reducer hooked to the back of the gage. Maybe the gage was never hooked up previously and I hooked it up when I put all the wires back...
I have not tried removing the wire of the ammeter but did remove the battery and like I said, it is still pegged.
ANY SUGGESTION ??????

It sounds like when the conversion was done originally, they put the wires on the back of the ammeter all on one terminal, thus bypassing it. When you hooked it back up (the way ot was f rom the factory) yes, it probably pegged it and it is now stuck. You may get lucky and a rap on the back of it with a screwdriver handle may un-stick it. Then you may want to put all the wires on one post and bypass it again.

From the Runtz instruction "Runtz voltage drops are NOT to be used with amp gauges...which are not voltage sensitive anyway, or tachometers. Runtz's are designed for dash gauges only." Your amp meter probably experienced a momentary direct short to ground during the rewiring process. Normal loads would not likely damage the amp meter and it does not care if 12 volt or 6 volt.

Mike...I tried tapping the back of the amp gage and the needle did not recenter itself so I removed the cluster again to get at the needle on the amp gage and I moved it to center manually with my fingers.There was no resistance to doing so and It stayed there until I re-hooked everything back up again. then it pegged again to C.
I took digital pictures and tagged everything as to where they went to before I removed the wires the first time.. I checked my pictures and everything is back to where it was before the Amp gage pegged but it pegged again the minute I turned on the iginition key.
Everything works in the truck including the after market under dash gages...So I am assuming that it is either shorted somehow or the 12V current cooked the amp gage because when I pull the battery cable off the gage remains pegged.
I did have the iginition out when i cleaned up the wiriing, maybe I changed where one of the ignition wire attaches.

Does the amp wire go to the Iginition post on the iginition switch or the battery post on the iginition ???????
The amp gage is for 6V so would it not peg out on 12V ??????????
Due to the fact that I have no use for an amp gage, If I leave it pegged out will it cause a problem of any kind ???????

Also, thanks 59FLEET for the info on Runtz not applying to the amp gage.

I would not feel comfortable with a pegging ammeter. Check to see if the wires get hot when it pegs. how is your volt meter wired? If all is cool, then un-peg your gauge one last time, then don't run current through it anymore. You can put all of the wires which are currently on the ammeter posts on on post while leaving the other post without any wires. Current will then go where it needs to go without going through the ammeter and your gauge will look right.

Carl....I also am not comfortable with the amp gage pegged. ..I believe the gage is damaged in some way as even with the battery disconected the gage is pegged...I can center it by hand when removing the cluster but it drifts back to C...I had had this cluster out several times and have not yet put all wires on one post but will do so tomorrow and will move the needle on the gage to center.
Better safe than sorry......
The after market under the dash voltage gage is hooked up to the ACC side of the Ignition switch and then a ground wire has been run to the dash itself.
Have not checked for heated wires but will do so.........Thanks.

I am not concerned about the ammeter catching on fire if it is left wired up as original.
I am worried about whether there is a dead short causing your ammeter to peg.
Simply taking the ammeter out of the picture will not solve a dead short somewhere else.

...I am now having an issue with not being able to shut the engine down. I am not talking about deiseling, I am talking about the engine running well with the key either on or off. Went for a ride yesterday and when I came home the engine would not shut down with the key...I spent today checking wiriing and can not seem to locate the problem.
I even went back to the original ammeter wiriing setup to no avail.
Correct me if I am wrong. ....the power goes from the battery to the starter to the alternator to the ammeter to the iginition switch.
I am leaning towards a problem in the iginition switch...Any suggestion are appreciated....

How confident are you with your entire wiring harness? Who put it in?
I don't play around very long with someone else's wiring work before I yank it all out and do it right.

The wiriing harness was in rough shape due to age...50% original wiriing and 50% add on wires with crimped connectors.
I now have replaced a few key wires and all is good for the moment . I will have to rewire at some point. Thanks for all the help guys...

You better not run that motor. You better disconnect the battery. You better check the wiring more carefully. What are you using to "check the wiring"? I would NOT use the AMMETER ever again. You have a volt meter. Do you have the foot start? or a solenoid? Do you have a wiring diagram for your truck? If you answer these questions, I will explain what to check. You obviously are NOT turning off the coil. That's how a motor stops. So just wait till we get this sorted. Make your own wiring diagram from following each wire. Get the rat's nest sorted and bundled in meaning full branch harness. Get the Ignition switch dropped down and hanging so we can test. Ammeters are a PITA and absolutely not necessary. Too many unprotected/unfused/previous owner wiring/no fusible links..... on these old trucks. That must be addressed. If someone is working on their wiring, they need to understand wiring. Otherwise they will cause issues. Our trucks basic wiring is very simple. It's not house wiring or appliance wiring. It's very easy to understand.
If you have time, please answer ALL the question above. Glad to help, late this evening. You have already received some great advice and explanation.

Assuming your ignition switch is working you probably have your alternator being excited by the ignition 12 volt power. Alternator keeps 12 volts on the coil side of the switch even after turning off the switch. Add an idiot light or other small resistance load in the excite wire and see if it fixes the problem. As stated, one needs to develop an understanding of automotive wiring or find someone that can fix these kind of problems. There are plenty of good books on the subject. I once watched a hot rod burn from bad wiring choices, it is not worth it.

Hi....the engine not shutting off problem seems to be cleared up. i removed all the wiriing from the gage cluster and from the iginition switch and replaced some questionable wires, also it appears that i had one wire on the amm meter that was hooked to the wrong position on the ignition switch.

answers to questions asked ...I have a foot starter. I do have a wiriing diagram. I used a test light to identifiy hot wires. I used a multi meter to make sure my iginition switch was working properly. It is working as it should.

I was not sure how to bypass the ammeter but it does not seem to work anyways. So I hooked it up as described below.

Here is how I have the wiriing hooked up now.
On the ammeter total of 5 wires, two on the D side of the ammeter and 3 on the C side of the ammeter.
On the D side = 1 wire to iginition switch battery posotion
On the D side = 1 wire to exciter wire on alternator

On the C side = 1 wire to starter
On the C side =1 wire to light switch
On the C side = 1 wire to voltage regular on the drivers side firewall

The ignition switch is wired as follows..
Battery position = 2 wires,one to ammeter C side and other is a fused wire to radio.
Iginition position = 2 wires, one to junction block (coil) on firewall,passenger side, and another fused wire to cigar lighter.
Accessory position = 4 wires,radio memory,electric wipers,directional flasher and after market gages.

I hpoe all this is clear enough to understand..............thanks

Alternator? with a VR and ammeter? UHG! An internally regulated Alternator puts out 4X the amps at 1/2 the RPM's and gets RID of the voltage regulator. If you are going to do a Alternator, get an internally regulated.

If you are using the ammeter and you think it does not work properly, then you are asking for trouble. If just the meter movement is burnt out you should be OK. Most of the amperage goes thru the shunt (a built-in bypass)...... so you are using the ammeter as a junction block. The voltmeter just needs one wire to it and a ground. All wires, big and small, need to go thru an ammeter. Better to leave it unwired (for looks) and let everything come thru a new fuse panel or fusible link.

Do you have a ballast resistor wired in?

The truck is still set up the way I bought it . Not planning to change the alternator unless this one craps out. If it did then I would get an internally regulated alternator and not use the VR on the firewal

Is there a way to test the ameter to be sure that it is not functioning as an ammeter ??????

I can move the ammeter needle in any direction I want to with my fingers and it seems to stay there.
I am not opposed to using the ammeter as a "junction bock" .....BUT....
I would like to bypass the ammeter if it still functions as an ammeter.

What would happen if I took the two wires from the "D" side on the ammeter and installed them on the "C" side with the other 3 wires ?
This was suggested by some else previously.

I have the voltmeter hooked up the iginition and a ground as you stated it should be.

This has all been said already but you asked:

If you put all wires on one side of the ammeter, nothing passes thru the ammeter. So it's just like splicing them together or attaching them to a terminal block which does the same thing. It would not matter which terminal of the ammeter you connected ALL of the wires to. You are just using the stud as a common connection point.

This makes no sense "I would like to bypass the ammeter if it still functions as an ammeter." bypass means: NOT USE.

If you hook up an ammeter like it's supposed be hooked up, needle should pop to near the middle when key is on. If you start the motor it should be around middle or charging. If you turn on headlights, it should go towards discharge and recover in time to middle/charge side.
If it pegs like you said in your first post, lots of things can be bad including the battery and/or miswired. This gauge can melt a lot of wires and connector shells.

Using the ammeter as a junction block is not the best way to bypass it. The only gauge I ever look at is the gas gauge. I prefer dash warning light for charging. I will notice that before a gauge.
Good luck.

OK...this is what I am thinking of doing.
install a fusible link in 2 areas, between the Alt & the ammeter and between the starter & the Alt.
Then I will bypass the ammeter by using one post on the ammeter to install all 5 wires.
Then I will install a fuse panel on the firewall so I can remove the 4 inline glass fuses to one location....

The comment that " I would like to bypass the ammeter if it still functions as am ammeter " is that I dont trust that gage and dont need it with the volt gage in place. So wether the ammeter is good or not I do not want to use it.
Thanks for all the info you have given me.

Can't say too much regarding your bypass method because I don't know how the whole truck is wired. But look at this recommendation for bypassing ammeter. I think you are doing basically close to that. However this is not showing your style of alternator/regulator system. This is a one wire, internally regulated system. Just use it as reference, nothing else.

You said you have a diagram. You must have at least two. One for the original truck wiring with generator and one showing how to hook up an externally regulated alternator to a voltage regulator. Hope you have the correct info for that.

Here is what I have found:
1. Batt terminal on Alt thru fusible link to battery pos.
2. Batt terminal on Alt to VR no. 3
3. "R" terminal on Alt to VR no. 2
4. F terminal on Alt to VR F
5. VR 4 to coil pos or switched Ign.

After hooking it up this way, see what other wires are left that you were planning on going to the ammeter and place them elsewhere depending on what they are. I now do not recommend using ammeter post as a terminal for ANY wires. I don't see any need for that at all. After you wire the list 1-5, any other left over "hot wires" probably have a switch to go to. Think about it. Check out what those 5 wires, you were talking about, are for. This is your chance to clean this up.

Not sure what your sensing wire/exciter wire is for. That sounds like internally regulated talk. Resistive wire, dash light/warning light talk.

Bottom line is when done: measure across battery, Approx: 12.4V-12.7V motor off.................. 13.5V-14.5V volts with motor running, medium high idle. Most of the charging is done at higher than idle RPMs.