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Discussion Starter · #641 · (Edited)
Started working on schematics to figure out the relays. The starter relay is to disable the vehicle with a remote. The purpose is to interrupt the wire to the starter if the ignition is turned on. The device has a two-minute delay so once the vehicle is parked after driving, it can not be restarted unless you have a remote. I added a bypass switch just in case the remote should ever fail for the remote relay (eBay stuff).

Looking at the drawings, I updated the thread and put the A/C into the mix. The fans should be on when the AC is running.

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I still have to put this in the truck. But I feel it is better to have a plan when I go out there. :geek:

11/20/21: I have edited the first diagram. Grounding the fan relay is the best trigger out there. I have three ways to activate the fans. It is done by grounding the fan relay with the toggle switch, 160-degree thermostat, or the trinary switch.

On 11/21/21 I added two relays 1) parking/running lights 2) Ground timer. This will allow the lights to shut off on a timed delay after the ignition is de-energized (key pulled out) Added the timer relays to the light circuits so they will time out probably 10 seconds to a minute after the key is turned off.

On 11/22/21 I saw some rather large issues with my schematics. The timer relay on the lights was not a good setup. Much better now. Also, I am wondering about the KSB and whether that needs to be on its own circuit. The setup looks good until you figure out if the AC is running, the fans are running and the KSB is energized. so the KSB can be energized while the engine is cold. I need to reconsider this and come up with a solution. I rewired the lighting schematic as well.


Here is a great video on how the system works: How To Wire A Trinary Switch To Your Car's Electric Fan - YouTube. It is a simplified and explained version of my wiring schematic.

Here is another on relays: How To Wire An Automotive Relay - YouTube

How to select a fuse: how to CALCULATE how big of a FUSE you need in your circuit (STEP-BY-STEP) - YouTube
 

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Discussion Starter · #642 ·
When I disassembled the truck, I was dismayed about the number of issues I was having with unbolding the front clip. The nuts were breaking off inside the fenders. Today was the day I dealt with the issue.

On this fender, five nuts broke off. This left empty square holes with no nuts on one fender and two missing nuts on the other fender.

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I welded some nuts to flat bar

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And cut the bar up to make small tabs to weld the nuts to. (of course, I pre-drilled the holes before hand.

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So with the flat bar tab with a nut welded, I drilled through the inner fender and tapped the hole for a machine screw to secure the nut in place.

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Cleaned it up and paint the inner fender with flat black.

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Discussion Starter · #643 · (Edited)
TRINARY SWITCH OR BINARY SWITCH (LOW-PRESSURE AC SWITCH).

Trying to figure out my wiring, I ordered and believed I needed a Trinary switch. However, you can rig another relay and use the regular (Low Pressure) switch (also called a Binary Switch). I have added two diagrams to show the difference. Originally, I was going to go with a Trinary Switch, but picked up a harness that will allow me to use the regular Binary Switch.

TWO DRAWINGS TO SHOW A TRINARY SWITCH SCHEMATIC VERSUS A BINARY SCHEMATIC.

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The basic operation for both is relatively straightforward. The relays have 12v from the ignition (when on) and 12 v from the battery/fuse panel. The trigger on both schematics is the ground. The ground is activated by 1) the temp switch 2) a toggle switch, or 3) the Trinary Switch or the AC relay. Once grounded the power can go through the relays to the fans and turn them on. From the earlier design, I added another relay to control the second fan through an independent relay. I also removed the KSB which will now have its own harness.
 

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Discussion Starter · #644 · (Edited)
Here is the KSB (wax, earlier version). The power is from the ignition switch to the relay which is the input to activate the relay. Power through a fuse will be the input to the KSB. The ground switch is a temp switch (the same type as the one used on the fan circuit) which will complete the relay circuit and activate the relay to send 12volts to the KSB which will melt the wax and retard the engine a bit. I decided to mount the temp switch for the fans at the back of the engine and the KSB on the inlet of the engine from the radiator.

11-27-21 I added a resister to the outlet of the relay to the KBS to reduce the current. This was based on char1355 and his comments on post 645 and the following four posts.

11-28-21 I added a drawing without the relay. This is simply a 12 volt wire that uses power from the ignition (tapped in on the fuel shutdown solenoid) and ran through the resistor to the KSB. It is simpler in design.

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Have you checked the wiring specs for the KSB. Those wax motor types have a special wire that has a built in resistance. Not sure who's bright idea that was but it's not just a normal copper wire. There are even instructions in the service manual about testing it to be sure it is functioning correctly. It's is also a darn expensive little piece of wire harness.
 

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Discussion Starter · #646 · (Edited)
Have you checked the wiring specs for the KSB. Those wax motor types have a special wire that has a built in resistance. Not sure who's bright idea that was but it's not just a normal copper wire. There are even instructions in the service manual about testing it to be sure it is functioning correctly. It's is also a darn expensive little piece of wire harness.
Thanks, Charles, I have not heard of the wire. I found a thread where you talk about the KSB and wiring issue

(23) ksb resistor | Cummins 4BT & Diesel Conversions Forums (4btswaps.com)

I will start looking there. :geek:

A couple of quick videos to understand resistors.

Ohms Law Explained - The basics circuit theory - YouTube
you tube what is a resistor used for? - Google Search
 

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From my understanding, the wire is supposed to have a certain amount of resistance to make the KSB function correctly. Here is a link to a Cummins service manual you may find very useful. It even shows part numbers for things like sensors and wiring harnesses. This manual is over 1000 pages long. The KSB info starts here on page 947 and up. https://constructionexcavators.tpub.com/TM-5-2420-230-24-2/TM-5-2420-230-24-200968.html
 

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Discussion Starter · #648 ·
Thinking about this, I only need to know the amount of resistance the wire has and add a resistor to my harness. The instructions state ensure the reading is less than 10 ohms. The KSB shown uses a 3-ohm resistor, but that doesn't mean that is the resistance required for my harness.
 

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Discussion Starter · #649 · (Edited)
WAX KSB TESTING/ INSPECTION:

Cummins 4BT – KSB Wiring Harness – Inspection

The wiring harness used on the wax motor style KSB can be inspected using a volt/ohm meter.
NOTE: Pin ‘C ’ of the metro-pack connector is blank on the wax motor style KSB wiring harness.


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Use a volt/ohm meter to perform a continuity check between port A ’ of the metro-pack connector and the female
spade connector at the fuel pump shut down solenoid connector.
Repair the wire if there is an open circuit.
Ohms Resistance – Less than 10.
Ohms Resistance – Less than 10.



The idea is the restrict current flow to the wax KSB. I can add a 3 to 10-ohm resistor to my configuration and achieve the same result as the stock harness.

I checked a wire in my garage (without a resistor inline) and found it was at 26-ohms. I can see where Cummins would reduce the current flow to the KSB.

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This is what I ordered on Amazon for $10.

Thanks, Charles for bringing this up.
 

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If you read the specs on the wiring harness for the solenoid version, it came with or without a resistor in the line depending on CPL. Would need a Cummins engineer to explain the real purpose of the resistance in the wire. Possibly has something to do with timing of when the KSB turns off.
 

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Discussion Starter · #651 · (Edited)
I wish I had access to one (Cummins Engineer). The fact that the wire has to measure below 10 ohms says volumes. The problem with any manufacturing is the improvements that need to be made over the years. Things are tested and tried or reworked due to cost-cutting. I may not have the exact solution to the issue, but I bet it is close enough. Much better than nothing at all. My hope is to stumble across someone who knows the facts of why a resistor is needed in the first place.

I have been researching how to install the resistor. It appears that one end needs to go to the 12v wire to the KSB and the other end of the resistor to a ground. Looking at the drawing from Cummins, it looks like they just tapped into the 12 v wire on both ends.

I appreciate your chiming into the conversation. I feel much more informed than if you hadn't joined. Cheers 🍺🍺🍺!
 

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It is a good possibility that wire was not all copper. May have been an alloy with some silver mixed in the get the resistance below 10 OHM. Of course the impedance can also depend on how pure that copper is. I used to deal in audio electronics and speaker wires were often rated in 9's. Two 9 would be 99% pure. Four 9 is 99.99% pure. Each increase in a 9 causes a big cost difference. When you got up to 99.9999% which is six 9 you're talking laboratory grade stuff. But that is cheap wire compared to six nine silver which will hurt your pocket book a bit.
 

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Discussion Starter · #653 · (Edited)
It sounds like it will hit my pocketbook. When I removed the wiring harness when pulling the engine from the Grumman van (10 years ago), I did not notice anything unusual about the wiring. But the wiring may have been an alloy. Hard to look back on all of those years and know. I will continue to research a bit and try to figure this one out.

On the other side of my day, I thread chased all of the nuts built into each fender and put the final coal of flat black paint on them as well. I also manufactured a bracket for the oil pressure sensor. Just in case, I do realize that I could run it straight from the block, but this has another pressure sensor I plan to employ for a low-pressure alarm. I will most likely hook it up on a relay with a time delay on feature. That will give me time to put the key in the ignition and start the truck before it goes off. I put this on temporarily. I still need to clean it up and paint it red to match the engine. I am also waiting for the 1/8 NPT male to -4AN male to connect to the block. Where the gauge is, is where the other pressure sensor will be. I left the oil pressure gauge in so I could start the engine this coming weekend.

Now, before anyone says anything, yes, I could have utilized both pressure ports on this side of the engine for the two sensors. To me, this simplifies the wiring as the 6.2 chevy diesel's oil pressure sending unit is in the same relative position. I also thought about mounting this on the firewall to reduce the vibration from the engine. That might still happen. Maybe a bracket off the hydro boost (brakes).

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Discussion Starter · #654 · (Edited)
Well, I got my hopes up today when the fitting I ordered for the lube oil pressure sensor came in. I verified the fitting with the Cummins website. It was a 1/8 inch NPT hole (according to the website). The fitting would only fit in less than 1/2 turn then it froze. I did not want to push it as I was dealing with the block. Turned out my 1/8 NPT x -4AN is the wrong fitting. I checked the plug that came out and found it was an M10.x 1.0 fine thread. So is the block! 😡 I ordered the right fitting today and should have it by Friday.

The wrong fitting: 1/8 NPT x -4AN
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Hopefully the right fitting: M10x1.0 x -4AN

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Block location:
Wheel Automotive tire Tire Motor vehicle Automotive exterior

To check, pull the plug and insert it into an M10x1.0 fine thread (thread checker).

Post thought: Looking at the block, it appears to be a mirror view of the 4BT block. While this is just an observation, on my truck the oil ports are on the other side. In fact, the whole orientation is mirrored. Obviously, I have too much time on my hands. 🙄
 

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There has been much confusion on the web about the threads in the oil holes. I believe Cummins change the threads when they went to the STORM block. The plug fitted into the unused hole is M10x1.00x13.5mm which is part 3678924. It also uses an O ring seal 3678925. There is another part 3678923 which is M10x1.00x9.5mm that was used on the engines with the STORM block. It is not a 1/8 NPT as some have stated for all engines. On early blocks it is part 3606619 which is a 1/8 NPT plug. You'd need to check your engine serial number to verify which plug you need.
 
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