Help Interpreting Wiring Diagram & Using Multimeter

[sriddle1]

I would remove K-1 Starter relay to disable the starter.There is another white "trigger" wire for the starter, but pulling the K-1 starter relay will do the same as removing the correct white wire.

I'll take a look, any hints where it is and by "Remove" does that mean physically remove or perhaps disconnect. Lastly, is dieselcrawler's White Wire #105 in his PIC coming off the K1 Start Relay. THANKS...........

 

[sriddle1]

Dieselcrawler, THANKS.............I'll take a look. I think the White Wire with the blue stakon was created by the previous owner to provide power to a sprayer, I followed the wire to a toggle switch and cable tied to the Roll-Over Safety Bar (forgot official name) with a connector on end. I will still take a look later this afternoon to see if I can see the other white wire similar to your..... Zebrafive might have an easier solution if I can find the K1 Relay..........

 

[Egon]

Is there a starter fuse?

 

[sriddle1]

OK, On the John Deere Parts Catalog, Model 790, Engine - 3TNV82A, Serial # 790056. Down in the Battery and Wiring Harness (790001-) Key #20 - M805280 RELAY, Qty 2 Remarks Column - STARTER, is that what we're talking about. Whenever I do an Internet Search on Starter Relay the results are always the Starter Solenoid, not the same, we're talking about the K2 Starter Relay :reading: Now I need to find one on-line to see what it looks like, the Parts Illustration Key # 20 looks like the relays attached to a bracket and a connector attaches, and then again, maybe not.......:reading:

 

[sriddle1]

Is there a starter fuse?

Egon, I didn't see one, in one of my first attempts to get the tractor started I pulled all the fuses (one at a time) checked and re-inserted. Here's the line-up from my "Official" 790 Operators Manual ....Position A-Seat Switch, B-Control Box, Fuel Solenoid, C-Warning & Turn Lights + Control Panel Lights, D,E,F,G SPARE, H-Flood Lights, I-Warning Lights, J-Tail Lights Switch, K-Headlights.

 

[sriddle1]

Finally... hope this works... refer to post #12 for reference.

Dieselcrawler, A bit slow on the uptake but I got it, yes I see the same lead..... Did some reading :reading: "Selenoid Operation for Dummies" and I see the trigger, as Zebrafive referred to it is the #105 Wht Wire. See if I have the logic - By pulling that connection it deprives the selenoids ability to connect the 12V to the motors windings and hence "No Crank" Just what I've been looking for. Additionally, I will be able to continue with Zebrafive's Voltage Checks and be assured no issues upstream and lastly, after reconnecting the Selenoid's connector to the harness, finally closing out with your physical inspection of the plunger retract...... could you just give me a thuimbs-up with my blue text and is there anything I should observe other than a simple retract of the plunger...... AGAIN, THANK's FOR THE HAND HOLDING...........

 

[dieselcrawler]

Yer set... blue text is spot on, starter can't engage, check for plunger to pull in... it's that simple.

 

[sriddle1]

Yer set... blue text is spot on, starter can't engage, check for plunger to pull in... it's that simple.

GREAT !

THANKS AGAIN for posting the pictures along the way, and THANKS to Zebrafive for his comprehensive Step-By-Step Fault Detect/Fault Isolate Process.

TGIF :drink:.......... Hopefully, tomorrow I'll be able to identify the faulty component. Get-er-done.........

 

[Zebrafive]

Sorry for the delay getting back to this thread. The starter relay is key 20 in the drawing. Just unplug it for your test. OR you can disconnect the "trigger" wire from the starter Solenoid, if that is easier. Same result, starter will not work when key is to "Start"

There is a difference between a relay and a solenoid, but no need to get into that here.

Good luck!

 

[dieselcrawler]

Don't forget to try to push the plunger in manually if it doesn't pull in on its own. It may hold in, but not until after the key has been in the start position.

Starter disabled, stop solinoid out, plunger accessible. Key to start position should draw in plunger, and hold in with key in run position. After key has been in start position, plunger should stay retracted if manually pushed in before key off.

 

[sriddle1]

Good Morning Dieselcrawler and Zebrafive,

Per dieselcrawler's skillful guidance I disconnected the # 105 Wht Wire from the Y1 Starting Motor Solenoid. :thumbsup:

Per Zebrafive's previous post (highlighted below) In the "RUN" Ignition Position vs. "ON", I performed Zebrafive's Voltage Check , at # X5 Connector for "Hold in" = Within Range, A-OK :thumbsup:

Went on to Zebrafive's Voltage Check at X5 Connector for "Pull In" and as I turned the key to the "RUN" Position, not yet advanced to the "START" Position, I noticed the voltage spike to 12 Volts for One Second. :thumbsup:

OBSERVATION FOR ZEBRAFIVE - Not sure if that Ignition Position is significant but since I successfully had both the "Pull In" & "Hold In" voltage to the # X5 Connector I plugged the Y2 Fuel Shutoff Solenoid back in, advanced the ignition to "RUN" and the answer is = NOT-TA, Nothing, no plunger retract. :thumbdown:

dieselcrawler and Zebrafive, Would you agree the Y2 Fuel Shutoff Solenoid is Bad, or, is there perhaps another anomaly at play......... :scratchchin: Any thoughts would be appreciated......THANK YOU..........

Now check the wire that matches up to the Red of the FS, (Green/White). Black meter lead to black wire of the connector. Red meter lead to wire that matches Red (Green/White) of the connector. PTO OFF, Neutral, Key ON. You should get 12-13 volts. This for the "hold in" coil of the FS

Now check the wire that matches up to the White of the FS (White/Blue). Black meter lead to black wire of the connector. Red meter lead to wire that matches White (White/Blue) of the connector. PTO OFF, Neutral. Key START. You should get 12-13 volts for ONE SECOND. This is the "pull in"
coil of the FS

 

[Egon]

Is there continuity on the solenoid?

 

[sriddle1]

Is there continuity on the solenoid?

Egon, Sorry I'm out of my element......Let's see continuity reading, aka ohm reading "No power applied": Three wires (Wht, Red, Blk) going to solenoid via its X5 connector. Hiimmm, where to place the probes for testing, I'm guessing" Test # 1 - Red Probe - Red wire, Black Probe to Blk Wire.....Test # 2 -Red Probe to Whit Wire and Black Probe to Blk Wire., Am I close ?

 

[sriddle1]

Don't forget to try to push the plunger in manually if it doesn't pull in on its own. It may hold in, but not until after the key has been in the start position.

Starter disabled, stop solinoid out, plunger accessible. Key to start position should draw in plunger, and hold in with key in run position. After key has been in start position, plunger should stay retracted if manually pushed in before key off.

dieselcrawler, Sorry, Just saw your post so I went back into the garage to re-check, I had not manually pushed in...... In "RUN" position plunger does not retract, In "START" Position plunger does not retract. In "RUN" position if manually pressed it stays retracted until I turn to "Off" Position.

egon, Based on that I'd say it should have continuity, I'm guessing...........

 

[Egon]

Egon, Sorry I'm out of my element......Let's see continuity reading, aka ohm reading "No power applied": Three wires (Wht, Red, Blk) going to solenoid via its X5 connector. Hiimmm, where to place the probes for testing, I'm guessing" Test # 1 - Red Probe - Red wire, Black Probe to Blk Wire.....Test # 2 -Red Probe to Whit Wire and Black Probe to Blk Wire., Am I close ?

Lordy, can't remember the colour coding!

Ground on the apex of triangle connector and then positive to the other connects each in turn. If there is an ohm reading there should be continuity. ( I think )

 

[dieselcrawler]

Can you bench test the stop solinoid? If its already unbolted, disconnect the wiring, use jumper wires from a battery? We can walk you thru it, but just to be sure the stop solinoid is in fact bad. Im saying it is, based on your reports.

 

[sriddle1]

Can you bench test the stop solinoid? If its already unbolted, disconnect the wiring, use jumper wires from a battery? We can walk you thru it, but just to be sure the stop solinoid is in fact bad. Im saying it is, based on your reports.

Good Morning dieselcrawler,

Finally getting a little rain here this morning, anything helps. I was planning to do some sort of a Bench Test this morning, looks like the "Pull In" Function (Wht Wire Test) on the Solenoid may be the issue. I "think" a simple Bench Test would consist of, FROM THE BATTERY: + to Wht Solenoid Wire, - to Black Solenoid Wire (For Pull In) and then, + to Green Solenoid Wire, - to Blk Wire (For Hold In). I was going to use Jumper cables with finish nails gripped on the ends and easily inserted into the connector housing.

Regarding a Replacement Selenoid, the PN information off the housing, Model: 1503ES-12S5SUC5S (WOODWARD / SYNCHRO START NO.) Part No. 119653-77950. According to a JD Parts supplier that corresponds with JD M8068081 @ $185.71 (GreenPartStore) and also need the O-Ring RG60092 @ $1.64. I tried looking for the Woodward Part on-line to save some $$$, not much luck. I saw OEM Replacements on EBay in the $30s, I'd be real concerned with their reliability (why temp fate) so looks like a JD Part will be what I purchase that is "if" the Bench Test indeed validates the "Pull In" is faulty.

dieselcrawler, Could you please give me a thumbs-up on the Blue Text before I proceed, also if you have any thoughts on the Replacement Solenoid that would be appreciated.

 

[dieselcrawler]

Not so simple... you will need to rig up a way to power both the red and white wires simultaneously.

Do you have any old wire scraps around?

 

[Zebrafive]

Good Morning Dieselcrawler and Zebrafive,

Per dieselcrawler's skillful guidance I disconnected the # 105 Wht Wire from the Y1 Starting Motor Solenoid. :thumbsup:

Per Zebrafive's previous post (highlighted below) In the "RUN" Ignition Position vs. "ON", I performed Zebrafive's Voltage Check , at # X5 Connector for "Hold in" = Within Range, A-OK :thumbsup:

Went on to Zebrafive's Voltage Check at X5 Connector for "Pull In" and as I turned the key to the "RUN" Position, not yet advanced to the "START" Position, I noticed the voltage spike to 12 Volts for One Second. :thumbsup:

OBSERVATION FOR ZEBRAFIVE - Not sure if that Ignition Position is significant but since I successfully had both the "Pull In" & "Hold In" voltage to the # X5 Connector I plugged the Y2 Fuel Shutoff Solenoid back in, advanced the ignition to "RUN" and the answer is = NOT-TA, Nothing, no plunger retract. :thumbdown:

dieselcrawler and Zebrafive, Would you agree the Y2 Fuel Shutoff Solenoid is Bad, or, is there perhaps another anomaly at play......... :scratchchin: Any thoughts would be appreciated......THANK YOU..........

I am not sure either if ignition position makes a difference. Your tests indicate the wiring to the Fuel Shut off is OK.

When you connected the FS and had no response, that would indicate failed part to me.

Because of the part cost, bench testing is worth a try.

Also a continuity test. For that set your meter to OHMS. Touch your red and black meter leads together. Meter should read ZERO OHMS. Some meters have an "OHMS adjustment" if the meter does not read zero ohms with leads touching, use the adjustment (usually a screw) to adjust for zero ohms.

Now to test, one lead to black, other to white or FS. If the meter does NOT move the coil is "open" meaning it has a break and current can not flow. Next test one lead to black and other to red of FS. When testing for continuity it does not matter which color meter lead is connected to the item being tested.

I do not know the spec for the FS coils. You should have some ohm reading. No change of the meter means "open" or break in the wire.

 

[sriddle1]

Not so simple... you will need to rig up a way to power both the red and white wires simultaneously. Do you have any old wire scraps around?

dieselcrawler, "SIMULTANIOUSLY" you say ???? When I did the Zebrafive Voltage Checks I verified the PULL-IN Voltage for one second and the HOLD-IN a constant in the RUN Ignition Position...... I thought the PULL-IN coil pulled the plunger in for a second and the HOLD-IN Coil held it in place until turned off......They seemed to be independent actions, I'll fall back on the old Master Sergeant Hans Georg Schultz on Hogan's Heroes: "I know nothing".....

With regards to extra wire not a problem, so per your direction, wire up both Solenoid RED & White simultaneously to Battery + Solenoid Black to Battery - . Are you thinking there's extra voltage to the PULL-IN Function if parallel wired in that fashion.