High voltage

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Torrance00

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Hey guys, I ran into an interesting situation the other day
and could use your help ASAP. I was driving and noticed an oder
then a wisp of smoke from my steering column, of course this
got my attention, and it happens after about 10 min of driving.
So needing to do other work under the dash I took the
steering wheel off, to remove the instrument panel and while
doing this I did some voltage checks on the wireing in the
steering hub. I found 2 places where it showed 17 + volts,
the (pink) on the plastic modual, and on the ignition switch
where the 3 wire's are attache, it's the lowest one of the three.
So if anyone has a reason for this voltage, I'd like to know.
Also there are a pair of "red" wires, connected into the
bottom of the ignition switch housing, that end up under the
dash, in my case one of the two wire's is not connected to
anything. I also have 2 orange wires that I can not find
where they go to or how they are powed on, although I suspect
they go to some dash lights,
Hope someone can help me today\this morning as I am trying
to get the 74 Dart back on the road..
Best
Dave
 
What is your battery voltage . Properly charged battery would be 12.45. To see any higher voltage in the system, you would have to be tapping into a stored energy source such as a condensor or capacitor.
 
When you took your voltage check you did not mention if the car was running or not. I suspect it was because you cannot get anywhere near 17 VDC from your car battery. That said, check the voltage at the battery while at a fast idle. If it really is 17 volts that's way too much, it should be closer to 14.2 VDC. If you're still reading high check your regulator, regulator ground, wiring etc. and/or the alternator itself.

You also may have a problem with your meter giving you a wrong reading.
 
funwithfuel said:
What is your battery voltage . Properly charged battery would be 12.45. To see any higher voltage in the system, you would have to be tapping into a stored energy source such as a condensor or capacitor.
Click to expand...

A condenser is a capacitor and it's only going to go as high as the battery voltage.
 
Measure again after disconnecting one of the small spade terminals on the alternator (either one). That will disable your alternator. As mentioned, the battery alone should never output more than ~12.6 V. Your multimeter may be reading incorrectly. If due to the alternator, you probably have excessive drops thru the bulkhead connector, ammeter connections, or ignition switch. A common problem with many posts.
 
As others said, first question is whether the voltage was measured with car running

1--If this voltage was measured with car running, the charging system is WAY WAY too high

2--If this voltage was measured, engine off, then your meter is not accurate.
 
the car was not running, volt at battery is around 12.5 - 13v..
no other circuit shows anywhere near this voltage. again
its a pink wire connected to the plastic modual in the steering hub and
the other is on the inside back of the ignition switch.
 
What "plastic module" are you referring to, the horn button?

What is this "other" on the back of the ignition switch?
 
1 about the meter... it show the battery at 13.17 with the car not running
2. I just installed the intrument panel, so at idle the battery now shows 18.2 v.
3. I can't find any info on what I think is an amp gauge -40 +40
but at idle it now show +40
I let the car idle for about 5 min to see if anything happen, the temp guage
started to rise, this is good, my gas gauge is not working properly

I would say my meter is correct, but something is very wrong.
someplace. probably stop and replace the voltage reg, it would be like
the third one if 2 years, but they can be bad from the factory...
well as long as the car does not catch fire, I"m ok..hahaha
Best
 
If the battery is being overcharged, and it sounds like it is, you may be measuring "surface charge" on the battery. Try shutting off the engine, and turning on the headlights for about 30 seconds, then measure the battery. It should be 12.5 or higher, but below 13

Check that the regulator is well grounded

Check supply voltage to your regulator. To do that, turn the key to "run" with the engine off. Hook one probe of your meter to the battery + post (hot post) and the other meter probe to the blue alternator field wire. You are hoping here for a very low reading, the lower the better.

If you read more than .3V (three tenths of one volt) you have a bad connection from the battery, through the harness, to the "ignition buss" which also feeds the regulator.

If the ground is good and this reading is good, make sure that the regulator wiring "has control." To test that, start the car and get the engine idling fast enough to show a charge on the ammeter. Then unplug the regulator connector. The alternator should stop charging.

If that happens, and your voltage check above was OK, replace the regulator.
 
One screwup that I found when my ammeter would peg on the high side was that the wrong wire was connected to the alternator field connector. My helper didn't realize that the voltage sense wire from the ignition switch to the voltage regulator is dark blue, while the field wire from the regulator to the alternator is dark GREEN. No connection to the field connector on the alternator results in the alternator running at full output. A wiring diagram is your friend! (So is an accurate voltmeter!) ((And, as others have pointed out, GOOD GROUNDS!!))

ATB

BC
 
67Dart273 said:
If the battery is being overcharged, and it sounds like it is, you may be measuring "surface charge" on the battery. Try shutting off the engine, and turning on the headlights for about 30 seconds, then measure the battery. It should be 12.5 or higher, but below 13

Check that the regulator is well grounded

Check supply voltage to your regulator. To do that, turn the key to "run" with the engine off. Hook one probe of your meter to the battery + post (hot post) and the other meter probe to the blue alternator field wire. You are hoping here for a very low reading, the lower the better.

If you read more than .3V (three tenths of one volt) you have a bad connection from the battery, through the harness, to the "ignition buss" which also feeds the regulator.

If the ground is good and this reading is good, make sure that the regulator wiring "has control." To test that, start the car and get the engine idling fast enough to show a charge on the ammeter. Then unplug the regulator connector. The alternator should stop charging.

If that happens, and your voltage check above was OK, replace the regulator.
Click to expand...
.................................................................................................
I would add that on your last test, when you unplug the field wire, if the output voltage stays the same, the alternator has an internal short or ground and needs repair or replacement. I've seen the insulators on the field connection go bad and full field the alternator.
 
cudamark said:
.................................................................................................
I would add that on your last test, when you unplug the field wire, if the output voltage stays the same, the alternator has an internal short or ground and needs repair or replacement. I've seen the insulators on the field connection go bad and full field the alternator.
Click to expand...

A very good point and something I forgot. So what he's saying, here, is to also unplug the GREEN field wire from the alternator. If it still continues to charge, unplug the BLUE wire and recheck. What can happen is that the insulator for one field connection is allowing that brush to be grounded. This can also happen from sloppy/ improper rebuilders, and in one case (pun intended) the pre--70 case of the alternator had been modified by the rebuilder to accept an INSULATED brush holder, but the sloppy rebuilder had ALSO installed the original type 69/ earlier GROUNDED brush.

This means one of two things can happen:

A--If you "happen" to plug the blue field wire onto the insulated brush, the thing will "full field" and continuously overcharge

B--If you happen to plug the blue wire into the grounded brush, it will immediately burn up your ignition harness!!!! which is not fused!!!
 
A lot of imput, thanks guys...
I think I solved the "problem" after installing the new VR it still showed
16.5v, so I put the battery on a charger, and let it charge overnight.
in the morning the amp gauge showed just on the plus side and the battery
was showing a charge of 15.5v, which althouhg still high, I think will come
down the more I drive the car. I think what happen is the amps in the battery
got very low, have no reason why it would do so, or what might have
caused it. I'll just keep an eye on the charging circuit to make sure.
on another subject I built my own IVR or instrument voltage regulator
using info from the net...$3.60 a transistor, a capacitor, and a heat sink
seems to work fine... be sure to use a max size 20g wire, I used
stuff around the garage, and it was like a 16g which is to stiff..
Best
 
OK at this point you may have one of two problems or a combo of both

1--The battery may be damaged, and may be adding to the problem. IF you can scare up a known good battery to borrow out of one of your other vehicles, try that and check charging voltage. It is important by the way to check voltage when the engine (regulator) is warm.

2--It is VERY important to check two conditions---the ignition supply to the regulator, and the regulator ground. To do that, do the following-----------

Put your meter on "low DC volts" and turn the key to "run" with engine off. Stick one probe onto the blue alternator field wire (backprobe the connector) and stick the other probe on the battery positive terminal. You are hoping for a very LOW reading, not over .3V (three tenths of one volt) If more you have a voltage drop problem in the igniton harness, and this is CAUSING an overcharge condition.

To check regulator ground, get the engine running at a fast idle, stick on probe of your meter directly onto the battery NEG post, and the other directly onto the mounting flange of the regulator. Be sure to "stab" through any rust, chrome/ paint. Again, you are hoping for a very low reading, and you should NOT read more than .2V (two tenths) Less is better, zero is perfect

If more, remove the regulator, scrape around the bolt holes and rear of the flange and re--install with star washers. Good idea to also treat the ignition box in this way. You can ALSO run a couple of no14 or larger ground wires, jumper one bolt on the ignition box to one bolt on the regulator, and then down to the engine block.


Also take steps to find out if your meter is accurate. Check one of your cars after sitting for awhile. A battery that is "up" but has no surface charge should be on the order of 12.6V
 
Great tips on the tests. My voltmeter is at 15.2 when cruising, so I did all these tests. Confirmed the voltmeter is accurate. My grounds are all good, but the reading from the blue field wire to + is 1.14. This means a voltage drop in the ignition harness. Whats next?
 
This is a common problem, drop in the harness as well as less common, drop in the ground path from battery to VR

The factory path is pretty much battery..........starter relay "big stud".........fuse link.........through the bulkhead connector............to the ammeter (RED)........out the ammeter (BLACK)..........to the under-dash welded splice...........to the ignition switch connector........through the switch.......out on the IGN1 "run" (usually dark blue)..............back out the bulkhead connector.........and branch off to ignition system, VR IGN terminal, alternator field on 70/ later, electric choke if used, etc etc. NONE OF THIS IS FUSED!!!

One way to "fix" (workaround) is to get a "Bosch" style relay and break the "ignition run" wire coming out of the bulkhead into the engine bay. Take the bulkhead end, and feed the relay coil and ground other end of the coil. Feed the relay from your "big stud" on the starter relay, with a fuse/ breaker, and connect the switched contact to the engine bay end of the "run" wire

Some relays have 2x "87's" and no 87A. 87A is normally closed, leave it unhooked. 2x 87's is a heavier duty relay, and the 2- 87 terminals are in parallel

87 connects to the switched load, the engine bay end of the "run" wire
30 is the main power feed, from the starter relay stud
86 is the + coil connect to the bulkhead end of the "run" wire
85 is ground. These two must not be reversed because there is a spike diode in most relays

0332209204_Drawing.gif
 
.............Overcharge the battery, short life, acid boiled out and all over the fender..........

15 is not "terrible" but there is reason to suspect "it will get worse." There are hundreds of posts on problems with ammeter/ bulkhead connector problems and harness problems. They do not get better with age. In some cases much of the drop is right in the ignition switch
 

I’ve done the ammeter bypass, run a direct charge wire from alternator to battery, headlight relay harness from Rob, checked every single connection I can see in the engine bay, used dialectic grease on every connection. With your advice, the problem is probably a combination of the ignition switch and the connection between the switch and the bulkhead. I like the idea of an ignition relay.
 
^^And that is why^^ exactly. When you eliminate everything else, there is STILL the switch and the switch connector
 
Could this be the problem? This is from a prior hack job stereo install. I’ve had it taped up. Could this be the reason for my voltage drop?

56D644A1-92A1-4CDC-88CC-E4C5ACBB5334.jpeg
 
Last edited:
Heh.......yeah.......solder or get a crimp connector and good pair of crimper pliers
 
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