mopower76
Well-Known Member
Yes, yellow at starter relay, ignition switch unplugged so key out of the equation.
Voltage problems, cutting out when hot
- Thread starter mopower76
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Yes, yellow at starter relay, ignition switch unplugged so key out of the equation.
mopower76
Well-Known Member
Ok, I removed the jumper between the yellow wires at the interlock relay (engine side) then I got under the dash and removed the interlock unit (green box) tested all connections at pins.
Put it all back together without the yellow wires jumped and re-tested.
Now - key off
0v at yellow wire at ignition harness to switch
0v at yellow wire at start relay
0v at brown wire at start relay
Here’s something I’ve completely forgotten about and have no idea what it would go to.
Key buzzer?
Horn relay?
Unused?
Red wire into plug has constant 12v (battery)
Put it all back together without the yellow wires jumped and re-tested.
Now - key off
0v at yellow wire at ignition harness to switch
0v at yellow wire at start relay
0v at brown wire at start relay
Here’s something I’ve completely forgotten about and have no idea what it would go to.
Key buzzer?
Horn relay?
Unused?
Red wire into plug has constant 12v (battery)
I got in a little bit agao and am a bit heat fried. This one I can answer quick.
The 5 ohm was originally used to keep the ECU from drawing too much current. I've not figured out how internally that worked. Someone with more knowledge and experience with transistors and circuits probbaly could if they were interested enough. But the bottom line is you don't need the 5 Ohm.
Correct. The 4 pin ECU does not use the 5 Ohm resistor. I don't think it makes a difference if its phyically removed or not -except if removing it means loose wires, then leaving it there is better.
The 5 ohm was originally used to keep the ECU from drawing too much current. I've not figured out how internally that worked. Someone with more knowledge and experience with transistors and circuits probbaly could if they were interested enough. But the bottom line is you don't need the 5 Ohm.
mopower76
Well-Known Member
Posted too quickly...
Now the rest of this is really confusing...
just had the alternator tested
So output is good, it’s a 116amp if it matters.
Re-tracing and testing wires to the voltage regulator now.
Thanks! Removed, I’m changing the plugs out for two pin plugs and capping off the unused wires.
Now the rest of this is really confusing...
just had the alternator tested
So output is good, it’s a 116amp if it matters.
Re-tracing and testing wires to the voltage regulator now.
What the heck is that?
A CS116 or something?
What's the rotor draw on that thing?
And 0.4 Volts ripple with 2 Volts acceptable?
I don't know what that's for.
Maybe one of the other guys here knows.
And did you follow what @67Dart273 was posting about with the current vs. voltage?
It's the key to troubleshooting with voltage drops.
If not, or not sure, take some time to study this post.
High Charging Rate. Found Voltage Drop Need Guidance Please
Then this one about field circuits and current flow.
Charging system troubleshooting
A CS116 or something?
What's the rotor draw on that thing?
And 0.4 Volts ripple with 2 Volts acceptable?
I don't know what that's for.
Maybe one of the other guys here knows.
And did you follow what @67Dart273 was posting about with the current vs. voltage?
It's the key to troubleshooting with voltage drops.
If not, or not sure, take some time to study this post.
High Charging Rate. Found Voltage Drop Need Guidance Please
Then this one about field circuits and current flow.
Charging system troubleshooting
mopower76
Well-Known Member
)
It’s the factory replacement alternator for a 1997-2001 Dodge Ram. It’s just a new replacement of what was on the truck I pulled the engine from.
It’s a 116 amp denso with 2 pin plug. I have the two field wires running to the two pins on the alternator.
I can’t find anything on these alternators, if they are internally regulated or not (I do not believe they are?) and
I’ve read elsewhere that hooking it up this way works with the factory voltage regulator but if there are other opinions I’d like to know what you think.
Again, I am going off what I have done in the past as I haven’t been able to find anything about running this exact set up. (Magnum motor/serpentine accessories and original wiring/ac/etc
And I didn’t notice the post about voltage vs current but I will go over the High Charge Rate and troubleshooting posts now.
mopower76
Well-Known Member
I have no idea what .4 ripple means...
Mattax, funny how close his charging issues and voltage readings are to mine.
“Also
use aligator clips and see if the voltage at the regulator drops or increases with higher rpms.
To hunt for the voltage drop.
While running, measure the voltage between regulator ground (attaching screw) and the battery neg post. This would show bad ground connections.
Then measure voltage between alternator batt stud and regulator feed (blue). This shows poor feed connection (most likely the biggest issue).”
I’ll be chasing this again, great read.
Definitely helps to understand voltage drops and current.
This all really helps. Thank you.
Sorry I missed or forgot you said in the very first post that its a 1998 magnum 360 with Denso alternator and serpentine belt, etc.
Ripple: Each winding in the alternator is produces alternating current. Looking at voltage vs. time on an osciliscope, it looks like a voltage wave. There's three (or more) windings producing overlapping waves. So for all practical purposes the voltage looks steady. But there is a slight fluctuation or ripple.
Flickering or pulstating Headlights
I don't if any Denso alternators are internally regulated. Certainly some are not. Should be able to look that up on an on line catalog.
I've not dealt with them myself. Slightly concerned that the field current draw is higher than the VR can handle. I may be concerned about nothing.
FWIW. Squareback draw
Notice in the alternator specs, the factory test is for current output at 1250 rpm. This is tested by putting an electrical load on the system and regulating the voltage.
Current is measured at the load (placed across the battery) or at the alternator.
5 amps needed for the field and ignition branch off before the battery.
I don't know what the parts store test results are really telling us.
For the time being, prob safe to assume your alternator is working fine.
I've had the same type of question before - its not specific to your experience.
let me dig it out. here it is. This is an internally regulated Delco 12SI alternator. Ripple allowance is similar. Seems high to me, but in reality functions OK.
Here's a test result for a similar SI-12 that is understandable.
Getting back to Chrysler type alternators.
This is for a revised squareback (late 70s until ?)
Ripple is .23 amps,
Current was tested at 13.2 Volts (so it will show higher current output than a factory spec)
Field current draw was 6.8 amps! That seems high compared to the older alternators - but I don't know if it was tested the same way.
Not sure how helpful any of this is to your current situation. Just some background.
Ripple: Each winding in the alternator is produces alternating current. Looking at voltage vs. time on an osciliscope, it looks like a voltage wave. There's three (or more) windings producing overlapping waves. So for all practical purposes the voltage looks steady. But there is a slight fluctuation or ripple.
Flickering or pulstating Headlights
I don't if any Denso alternators are internally regulated. Certainly some are not. Should be able to look that up on an on line catalog.
I've not dealt with them myself. Slightly concerned that the field current draw is higher than the VR can handle. I may be concerned about nothing.
FWIW. Squareback draw
Notice in the alternator specs, the factory test is for current output at 1250 rpm. This is tested by putting an electrical load on the system and regulating the voltage.
Current is measured at the load (placed across the battery) or at the alternator.
5 amps needed for the field and ignition branch off before the battery.
I don't know what the parts store test results are really telling us.
For the time being, prob safe to assume your alternator is working fine.
I've had the same type of question before - its not specific to your experience.
let me dig it out. here it is. This is an internally regulated Delco 12SI alternator. Ripple allowance is similar. Seems high to me, but in reality functions OK.
Here's a test result for a similar SI-12 that is understandable.
Getting back to Chrysler type alternators.
This is for a revised squareback (late 70s until ?)
Ripple is .23 amps,
Current was tested at 13.2 Volts (so it will show higher current output than a factory spec)
Field current draw was 6.8 amps! That seems high compared to the older alternators - but I don't know if it was tested the same way.
Not sure how helpful any of this is to your current situation. Just some background.
mopower76
Well-Known Member
Hey man, any info that I don’t know is good info in my book!
Any ideas on this plug? What it is...?
Red side has constant power.
Any ideas on this plug? What it is...?
Red side has constant power.
67Dart273
Well-Known Member
Where abouts did you find it? This is in the instrument/ under dash harness?
I'd guess seat belt buzzer
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mopower76
Well-Known Member
It is under the dash on the drivers side by the fuse box.
I was guessing a buzzer too, should I add one to complete a circuit here?
I’m sure I’ve left them out of all of my other Mopars except the 71 Cuda... and it makes me kind of smile the first time it comes on... The nostalgia of that warbled buzz wears off rather quickly.
I was guessing a buzzer too, should I add one to complete a circuit here?
I’m sure I’ve left them out of all of my other Mopars except the 71 Cuda... and it makes me kind of smile the first time it comes on... The nostalgia of that warbled buzz wears off rather quickly.
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I'm with Del, some of what you found and posted on previous page doesn't make sense. If the yellow wire to starter relay is hot at all times the starter would run any time the neutral safety side of the relay is completed to ground. No doubt you have a short circuit somewhere, But where? Good hunting
mopower76
Well-Known Member
Thanks, I know it doesn’t make sense and that’s why I’m on this site!
The information obtained here is so valuable, I learn something new every time I post or search.
PS - I’m going to have to start completely from the start because now I’m getting different readings after messing with the seatbelt interlock module.
If I ever buy another Mopar that has this system it will be swapped (dash and charging harnesses) with a year that did not have it.
mopower76
Well-Known Member
So after going back through everything, voltage stays consistent everywhere I check until I get to the ignition switch plug, is there a way to check the ignition switch? I think I’m going to just replace the switch wiring in the column as everything keeps pointing to it as a possible problem and the plug itself is split in half from me pulling it apart multiple times to test.
mopower76
Well-Known Member
Is there anyway to keep testing the under hood connections bypassing the starter switch wiring at the column? Until I get a new starter switch installed?
Also I keep reading that aftermarket switches may not be plug-and-play, like they are one size fits all? But will need to be modified per vehicle year?
If there is a recommended source for getting a correctly pinned ignition switch harness for a 1974 please let me know.
Also I keep reading that aftermarket switches may not be plug-and-play, like they are one size fits all? But will need to be modified per vehicle year?
If there is a recommended source for getting a correctly pinned ignition switch harness for a 1974 please let me know.
mopower76
Well-Known Member
Believe it or not I just ran to my storage unit and started thrashing through boxes and found this
It has some interesting extra instructions that come with it that simply do not match what is in the car now
The new switch has a single black wire where a orange wire should be and then two blank spaces where the original plug has two small gauge red wires running up to the switch. These are solid black and black w/yellow tracer going into the dash harness.
I’m assuming these extra wires are for the stupid seatbelt interlock system…
Once I get the old switch out I will compare and post pictures of what I find.
This is the new plug
It has some interesting extra instructions that come with it that simply do not match what is in the car now
The new switch has a single black wire where a orange wire should be and then two blank spaces where the original plug has two small gauge red wires running up to the switch. These are solid black and black w/yellow tracer going into the dash harness.
I’m assuming these extra wires are for the stupid seatbelt interlock system…
Once I get the old switch out I will compare and post pictures of what I find.
This is the new plug
mopower76
Well-Known Member
And this is the original
67Dart273
Well-Known Member
Some of the extra wiring is for the "key in" buzzer and key light. "I don't" need any of that LOL
Best way to check a switch is to look up the terminals on the diagram and check it UNDER LOAD. That is more than a test lamp or multimeter. One good way is to use something like an old headlamp. 'Rig' clip leads on it so you can wire it up. Put the key in "run" and wire the headlamp up to the "run" output wire, and batttery NEG, and wire the battery hot to the switch main wire. Now with it hooked up and lit, wiggle the key to see if it flickers. Take a voltmeter and put one lead on the main wire into the key (power) and the other lead on the "run" wire. This will measure voltage drop across the switch contacts. There should be very little, perhaps .2V (2/10 of one volt) the less the better. Again, wiggle the key to see if it jumps around.
Best way to check a switch is to look up the terminals on the diagram and check it UNDER LOAD. That is more than a test lamp or multimeter. One good way is to use something like an old headlamp. 'Rig' clip leads on it so you can wire it up. Put the key in "run" and wire the headlamp up to the "run" output wire, and batttery NEG, and wire the battery hot to the switch main wire. Now with it hooked up and lit, wiggle the key to see if it flickers. Take a voltmeter and put one lead on the main wire into the key (power) and the other lead on the "run" wire. This will measure voltage drop across the switch contacts. There should be very little, perhaps .2V (2/10 of one volt) the less the better. Again, wiggle the key to see if it jumps around.
mopower76
Well-Known Member
These extra instructions are not Applicable in my opinion…
Also where it says C note that’s the black wire where the lighting wires in orange come into the other harness plug.
That’s a loan wire coming from the light bulb in the column shift selector, am I able to just splice it into the existing black wire on the new plug?
Also where it says C note that’s the black wire where the lighting wires in orange come into the other harness plug.
That’s a loan wire coming from the light bulb in the column shift selector, am I able to just splice it into the existing black wire on the new plug?
mopower76
Well-Known Member
Splice these two together or do away with the black wire from the switch altogether?
mopower76
Well-Known Member
Old vs new, pinout is different but when plugged in everything operates as normal.
Plus I believe this may be a point of problem.
These are the readings I just took using the old and new plugged in.
Old at red wire
New at red wire
Plus I believe this may be a point of problem.
These are the readings I just took using the old and new plugged in.
Old at red wire
New at red wire
mopower76
Well-Known Member
Old at blue wire
New at blue wire
New at blue wire
It seems like your your throwing darts.
I understand you are seeing power in odd places. So figure out what is connected to what and make corrections as needed.
My suggestion is get out your '74 manual, and either on the computer or some paper, draw the circuits you are working on.
Make an extra copy and mark up what you find on your car.
Then instead of red, yellow, white; you can call them by what they do.
I'd start with the power feed to the ignition switch.
This is the only one that should have power in it when the battery is connected. If anything else going to the steering column has power in it, stop and figure out why.
On the switch side of the connector, you don't need power to figure out what goes where. Just use continuity. Once everything is going to the correct place ,then and only then, look for resistance. (That's voltage drops when current is flowing. And what 67Dart273 is telling you is that small current won't reveal a moderate resistance.)
So for the '73 diagram, the column switch connector is CI 5, and power is supplied by the 12 gage red wire.
In the '73 diagram, it looks like M16 could be hot all the time as well.
If J1 is the only terminal with power, then go to the other half of the connector and make sure there is no continuity between 12 gage Red and any other termninal.
Then turn the switch to Start, and there should be continity between 12 Red and 12 Yellow and 12 Brown, and no other terminals. Then check Run.
Keep going.
Look at your '74 book and draw out what you need in a way that you can read what each does and connects to.
The factory diagrams were intended to have all the info, and the techs were expected to pull out what was needed to make a schematic. I don't know how jobs like that got billed! But IMO that's what you got to do.
I understand you are seeing power in odd places. So figure out what is connected to what and make corrections as needed.
My suggestion is get out your '74 manual, and either on the computer or some paper, draw the circuits you are working on.
Make an extra copy and mark up what you find on your car.
Then instead of red, yellow, white; you can call them by what they do.
I'd start with the power feed to the ignition switch.
This is the only one that should have power in it when the battery is connected. If anything else going to the steering column has power in it, stop and figure out why.
On the switch side of the connector, you don't need power to figure out what goes where. Just use continuity. Once everything is going to the correct place ,then and only then, look for resistance. (That's voltage drops when current is flowing. And what 67Dart273 is telling you is that small current won't reveal a moderate resistance.)
So for the '73 diagram, the column switch connector is CI 5, and power is supplied by the 12 gage red wire.
In the '73 diagram, it looks like M16 could be hot all the time as well.
If J1 is the only terminal with power, then go to the other half of the connector and make sure there is no continuity between 12 gage Red and any other termninal.
Then turn the switch to Start, and there should be continity between 12 Red and 12 Yellow and 12 Brown, and no other terminals. Then check Run.
Keep going.
Look at your '74 book and draw out what you need in a way that you can read what each does and connects to.
The factory diagrams were intended to have all the info, and the techs were expected to pull out what was needed to make a schematic. I don't know how jobs like that got billed! But IMO that's what you got to do.
mopower76
Well-Known Member
That’s great advice, I will do that moving forward.
For now what I was trying to show was the differences in voltage from the old switch to the new switch.
Old switch had 11.94v at red J1 with key off nothing else has power, then key on blue J2 and yellow S2 were reading 11.87.
Red J1 on the new switch has 12.63 constant (same as battery) with key off and nothing else has power. When key is on yellow S2 and blue J2 had 12.00 volts.
I was just trying to show the voltage differences between the old and new switches, doing nothing else but changing switches. (Even if the voltage readings are still wrong, at least they are moving in the right direction)
Obviously this was part of but not all of the problem.
I don’t have a lot of time to work on it but I’m trying to eliminate issues where I can. Progress is slow but at least it’s progress.
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