Starter solenoid wire identification

[ag4ever]

I’m at a loss how jumping the neutral safety switch fixed the lack of voltage in the switch circuit, but if it cranked by jumping the NSS the next step is to test if the switch is bad or if the transmission linkage is out of adjustment.

I would start by removing the interior shifter bezel. It should be floor mounted and look like this:


Removing the black bezel will reveal the shifter that looks similar to the part on the left.

Once that is removed, the gates will not interfere with the transmission shift points. You will need to ”feel” each shit point and when the internal indents catch. Shift into park and test for continuity from a good ground to the black wire from the NSS (or voltage from the positive terminal to the black wire). Shift to neutral (after ensuring the wheels are chocked) and test again. If you don’t get continuity (or voltage) you have a ground issue. Either the NSS is bad (doubtful) or the ground path to the transmission is bad.

Sometimes just wiggling the shifter is enough to get the NSS working. I have to do that occasionally. And sometimes it does not like park, but will start fine in neutral.

You can test continuity with your meter by using one of the white settings on the right (2000k Is a good one to start with). When testing continuity, you don’t want voltage, so always stay on one side of a circuit (negative to negative or positive to positive), never connect negative to positive. Most meters will beep or buzz when you have good continuity.

 

[Randyzzz]

You will need to ”feel” each shit point and when the internal indents catch.

I think you meant "shift point"!

I had to wipe the coffee off my keyboard. Thank you for the first laugh of the day!

 

[ag4ever]

I think you meant "shift point"!

I had to wipe the coffee off my keyboard. Thank you for the first laugh of the day!

oops.

 

[barrys]

I think you meant "shift point"!

I had to wipe the coffee off my keyboard. Thank you for the first laugh of the day!

I caught that too. Laughing out loud at lunch, nothing in my mouth at the time?

 

[CJocho]

With the few spare minutes I had during lunch I tried to tackle the next few steps as outlined by ag4ever. Without fail the boot had some pretty rusty screws with virtually non-existent phillips channels in the heads. After a few minutes with the dremel I was able to get a straight edge scored across my two problem screws. Luckily that did the trick.

I then took the photos shown below. I shifted the lever back and forth with ease and ability to catch each position. Then, because this Postal came with a see-through floor, I was able to watch the linkage move as I went from park to neutral, neutral to drive, etc., etc. I'm not sure if it matters, but I never saw the linkage sitting above the transmission linkage move. I took a closer look and it seems like the links should be connected somehow. Is that right? Could this be my problem? By the time I finished fiddling it was time to head back to work. Ill try to get to the rest of the testing this evening after the boys go down for bed..

 

[ag4ever]

The linkage rod that goes towards the back (near the NSS) is your SHIFT rod. (I think I spelled it right, no?)

The linkage rod that goes forward is the throttle kick down.

The rear linkage must move with the shifter.

The forward linkage must move with the throttle (After 1/2 throttle, give or take some).

The wiring in that photo goes to the Neutral Safety Switch (NSS) that is being discussed.

The throttle kick down linkage adjusts the line pressure in the transmission for various situation, not only for full throttle gear selection purposes. (Just a little extra info )

 

[CJocho]

I’m at a loss how jumping the neutral safety switch fixed the lack of voltage in the switch circuit, but if it cranked by jumping the NSS the next step is to test if the switch is bad or if the transmission linkage is out of adjustment.

I would start by removing the interior shifter bezel. It should be floor mounted and look like this:
View attachment 85825

Removing the black bezel will reveal the shifter that looks similar to the part on the left.

Once that is removed, the gates will not interfere with the transmission shift points. You will need to ”feel” each shit point and when the internal indents catch. Shift into park and test for continuity from a good ground to the black wire from the NSS (or voltage from the positive terminal to the black wire). Shift to neutral (after ensuring the wheels are chocked) and test again. If you don’t get continuity (or voltage) you have a ground issue. Either the NSS is bad (doubtful) or the ground path to the transmission is bad.

Sometimes just wiggling the shifter is enough to get the NSS working. I have to do that occasionally. And sometimes it does not like park, but will start fine in neutral.

You can test continuity with your meter by using one of the white settings on the right (2000k Is a good one to start with). When testing continuity, you don’t want voltage, so always stay on one side of a circuit (negative to negative or positive to positive), never connect negative to positive. Most meters will beep or buzz when you have good continuity.

Ag4ever,

In your instructions you say to:

"Shift into park and test for continuity from a good ground to the black wire from the NSS (or voltage from the positive terminal to the black wire). Shift to neutral (after ensuring the wheels are chocked) and test again. If you don’t get continuity (or voltage) you have a ground issue."

In this test, if I'm checking for voltage, would the black wire be the same NSS wire I tested earlier at the solenoid? I'm sorry if this is a dumb question, I just want to make sure I'm doing this correctly.

 

[FLCJ8]

I then took the photos shown below. I shifted the lever back and forth with ease and ability to catch each position. Then, because this Postal came with a see-through floor, I was able to watch the linkage move as I went from park to neutral, neutral to drive, etc., etc. I'm not sure if it matters, but I never saw the linkage sitting above the transmission linkage move.

How many and what color wires are connected to the NSS at the transmission?

 

[CJocho]

How many and what color wires are connected to the NSS at the transmission?

3 wires. Red, white, and black.

 

[ag4ever]

Red and white are for the reverse lights. Black is the ground for the starter solenoid.

In a continuity test you are not looking for voltage, but to see that point A connects to point B with little to no resistance. In this test the meter is set to ohms (upside down horseshoe).

Other option it one lead of the multi meter to the positive terminal of the battery, other to the end of the black wire at the solenoid. In this test the meter is set to DC volts, and the 20v setting.

Either way, you are checking for a ground path through the NSS and back to the battery.

 

[FLCJ8]

3 wires. Red, white, and black.

Okay,
The red should be "hot" when the key is "on" or "run", the white goes to the back up lamps, the black is the ground signal to the solenoid.
Since your NSS appears to be easy to access it is a simple test to confirm your NSS is functioning properly.

With the key switch on, test voltage from the red positive lead to various ground locations until you get a ~12 volt reading. This confirms you have voltage available at the lead.
Now keep the positive meter lead connected to the red lead and connect the negative meter lead to the center post of the NSS, you should get the same voltage ~12v when the shifter is in Park or neutral.
If you don't get a voltage reading from the switch, confirm you have a good ground at the transmission by touching the negative lead to the transmission housing. If you now get a good voltage reading you have a problem with the function of the switch.
While you are at the transmission testing you can also test your black wire running back to the solenoid, ground the black lead that is at the solenoid to the battery negative post.
Now test (with the key in run position) from the red hot lead of the VSS cable to the black lead that you connected to the battery negative post. If the wire is good you should get a good voltage reading.

 

[FLCJ8]

Well I see after I posted that ag4ever condensed my novel
Basically there are several ways to methodically break the system down to locate your problem area.

 

[CJocho]

With my multimeter set at DC 20, I obtained a reference measurement from the battery of 12.20. Then I placed the negative lead of my multimeter on the NSS wire (black wire), while simultaneously connecting the positive lead of the multimeter to the positive post of the battery. The reading I got was 1.2.

I then set my multimeter to 2000k ohms. Upon doing so the display read "1." I then placed one lead from my multimeter to the black NSS wire and the other lead of my multimeter to the alternator housing ( believed to be good ground). The reading on my multimeter stayed at 1 the entire time.

Am I to assume then that my problem is a grounding issue with the transmission? If so, how would one fix that?

 

[FLCJ8]

With my multimeter set at DC 20, I obtained a reference measurement from the battery of 12.20. Then I placed the negative lead of my multimeter on the NSS wire (black wire), while simultaneously connecting the positive lead of the multimeter to the positive post of the battery. The reading I got was 1.2.

If I'm reading this correctly you basically redid part of your original testing.
In my "novel" you would test the NSS itself.
It is a mechanically controlled switch dependent on the gear selector position that gets its ground reference by its contact with the transmission housing that eventually returns back to the battery negative post.

By testing from a good known "hot" to the center post of the switch itself you're determining the operation of the switch. (The center post should only provide a ground return path when in park or neutral.)
By testing from a known "hot" to the transmission case you are confirming the ground return path for the NSS.
By testing from a known "hot" to the black NSS wire that you temporarily ground at the opposite end you are confirming continuity of the wire in your harness.

I find using the vehicle battery as the positive or negative reference while testing to be more informative as you are comparing to a known reference voltage rather than an arbitrary resistance reading that depends on how well you make contact at the test points. As well the vehicle battery has a higher capacity than the battery that is in the meter. It also speeds up testing by only using one setting on the meter.

A good old fashioned test light in some cases will actually give better results than a multimeter because it will create a greater load on the circuit that's being tested than the electronics of the multimeter. The intensity of the incandescent lamp can reveal problems that are difficult to find with just a multimeter. But, that is a lesson for another day.

 

[CJocho]

If I'm reading this correctly you basically redid part of your original testing.
In my "novel" you would test the NSS itself.
It is a mechanically controlled switch dependent on the gear selector position that gets its ground reference by its contact with the transmission housing that eventually returns back to the battery negative post.

By testing from a good known "hot" to the center post of the switch itself you're determining the operation of the switch. (The center post should only provide a ground return path when in park or neutral.)
By testing from a known "hot" to the transmission case you are confirming the ground return path for the NSS.
By testing from a known "hot" to the black NSS wire that you temporarily ground at the opposite end you are confirming continuity of the wire in your harness.

I find using the vehicle battery as the positive or negative reference while testing to be more informative as you are comparing to a known reference voltage rather than an arbitrary resistance reading that depends on how well you make contact at the test points. As well the vehicle battery has a higher capacity than the battery that is in the meter. It also speeds up testing by only using one setting on the meter.

A good old fashioned test light in some cases will actually give better results than a multimeter because it will create a greater load on the circuit that's being tested than the electronics of the multimeter. The intensity of the incandescent lamp can reveal problems that are difficult to find with just a multimeter. But, that is a lesson for another day.

FLCJ8,

I appreciate the "novel" of information and suggestions. The amount of help being provided to me is much appreciated. I should have a half an hour or so this evening to give it another go and test the NSS itself. I do have a couple of questions about your procedure.

1. What do you mean by "center post" of the NSS?
2. Can my "hot" just be the end of the solenoid that is connected to the positive termimal of the battery?
3. What position does the key need to be in during these tests?

Once again, I'm sorry if my questions are elementary. I'm pretty confident with my abilities with analog things but how electricity actually works in a car is just so foreign to me.

 

[ag4ever]

See your picture marked up:



I think the next step is cleaning the oil / dirt from around the switch. Then remove the plug from the switch. Place the negative lead from your multimeter on the center pin of the switch (with the wires removed) and positive to the positive battery terminal. This will remove some of the wiring between the solenoid and the NSS.

What we are doing is narrowing down exactly where your break in the circuit is.

Another thing to check is a 4 wire plug under the brake booster. It should have a red, white, black, & orange wire. This is the same wire we are tracing that goes from the solenoid to the NSS.

 

[CJocho]

See your picture marked up:

View attachment 85888

I think the next step is cleaning the oil / dirt from around the switch. Then remove the plug from the switch. Place the negative lead from your multimeter on the center pin of the switch (with the wires removed) and positive to the positive battery terminal. This will remove some of the wiring between the solenoid and the NSS.

What we are doing is narrowing down exactly where your break in the circuit is.

Another thing to check is a 4 wire plug under the brake booster. It should have a red, white, black, & orange wire. This is the same wire we are tracing that goes from the solenoid to the NSS.

View attachment 85889

The first thing I did was get my brother's circuit tester instead of using the multimeter. I attached the positive lead of the circuit tester to the positive post of the car battery. I then removed the plug from the switch.

With the gear lever in the park position, I touched the tip of the circuit tester probe to the center post of the switch. This caused the light within the tester to illuminate thereby showing my a complete circuit. I then moved the gear lever into the neutral position and repeated the process. Once again the light in the tester illuminated. I then tested the circuit in every other gear lever and as expected, the light never illuminated. As a result, it looks like the NSS is working properly.

With the same setup, I also touched the transmission housing with the probe and it illumimated. I guess this is another confirmation that the transmission itself is properly grounded. I then turned my attention to the plug and its wiring to the solenoid.

The first thing I did was get a jumper cable attached to the negative battery terminal. I then connected the other end of that jumper cable to the end of the black NSS wire that would normally be attached to the solenoid. I then placed the end of the probe into each of the three female terminals in the plug. The terminal connected to the white wire completed a circuit, while the other two did not.

I then went to the firewall and disconnected the connection between the NSS and the solenoid. My intention was to see which section of the wiring was causing the short circuit. I then tested the section of the line from the firewall to the solenoid. I was able to complete the circuit when I touched the probe into the female terminal for the black wire.

I then tested the section from the NSS to the firewall. In looking at that section of the wiring, it appeared that the terminals closest to the firewall were green in color and corroded. I attached the jumper cable (my ground) to the terminal the black wire was feeding into. I then placed my probe into the center female terminal of the plug which appears to feed into the black wire. This test resulted in no connectivity (the testing light did not illuminate). Soooo...am I to understand correctly that either the section of wiring from the plug to the firewall is defective, the center female terminal of the plug is defective, or the male clip of the harness is defective? Can the plug or clip be fixed or is it just easier and cheaper to buy a new assembly?

 

[ag4ever]

Looks like you found your issue.

Now, you get to find the precise location of the issue, or try to get a replacement section of the harness. I’m not sure what connectors those are or if the are still available. Next issue will be finding a wire harness for a RHD Jeep as the wire routing is different than the LHD auto Jeeps.

I would first suggest following the black wire from the connector to connector to ensure it was not cut at some point. If it appears to be intact, then replacement might be in order.

 

[FLCJ8]

Soooo...am I to understand correctly that either the section of wiring from the plug to the firewall is defective, the center female terminal of the plug is defective, or the male clip of the harness is defective?

From your description of your testing procedure I would say yes.

I would suggest using the piercing tip of the test light to check the wire a short distance away from the plugs.
You can alternate (if necessary) which end you ground to determine if the wire is the issue or which terminal end is the problem.

I would pierce the wire where it is easy to tape and then seal with "liquid tape"

 

[CJocho]

I got it all all sorted out. Thank you to all that helped me. Now it's time to run a fuel line and get the brakes working properly.