Help Interpreting Wiring Diagram & Using Multimeter

[dieselcrawler]

Sorry I havent been much help lately, I've barely kept up with reading the new progress posts, let alone think about and understand the details...

Glad you are keeping at it...

 

[sriddle1]

Sorry I havent been much help lately...

dieselcrawler,

Don't think that at all, you and Zebrafive have given me the support :thumbsup: to go beyond my skill mix in trying to solve this issue which hopefully will be beneficial down the line for others with this same issue. :reading: Your combined technical assistance also helps me counter the local JD Shop's initial estimate (without even looking at the Tractor) = $ 250.00 pick-up/delivery + $70.00 shop hour (Meter Running). :greedy: As show in the attached PIC, my 790 died in the back of my garage facing forward with the FEL installed and down. When I got the initial estimate I asked: "Say, how ya gun-na get the tractor out of the garage with the FEL down & without damaging to my 2 years old slab?.. :scratchchin: a long pause then; "We'll have to adjust the pick-up fees to account for that" (Meter Running) :greedy: .... I figure worse case scenario I could replace everything (K1 Start Relay, K2 Fuel Relay. Y2 Fuel Shutoff Solenoid & A1 Time Delay Control Module for around $500.00. The only trick, to get in a contorted position and further investigate what's what while waiting for the shop Manual on CD + ID the mystery K2 Fuel Relay's PN from JD.....as I mentioned I didn't see it on the JD Catalog..........

 

[Zebrafive]

My guess is since parts shows TWO key 20 relays, one is starter, the other fuel. You might be able to ID them by their wire colors on their connectors.

 

[dieselcrawler]

Simple relays can be tested reasonably easy. Time delay could also be tested, but I'd have to look more closely at exactly how... Simple in theory, where to put power to the coil and where to measure with an ohm meter to determine proper operation is where the questions come into play.

Edit: swapping relays (starter with fuel, for example) would give you an easy test port...

 

[Egon]

Want move the tractor pry up the bucket and slip a rope, cable, chain under it and attach to the front of the frame. When you pull the cable tightens and lifts the bucket.

 

[sriddle1]

My guess is since parts shows TWO key 20 relays, one is starter, the other fuel. You might be able to ID them by their wire colors on their connectors.

Aaaa-Haaa, the old quantity of (2) with a general description in the RMKS routine........Wow, I'd say pretty sloppy for JD Engineers to have done that since they have differing functions (Start & Fuel) although the same PN = M805280. You'd think the REMARKS Column would shed some light, anyway..... Yes, I agree with you assessment, follow the wire colors......I should be able to swap both out rather easily at $32.80 a piece since I'm inside the critter den which looks to be rather tight and the one relay is on the back side of the Key 22 Bracket. I'll investigate tomorrow, will report out. Finally raining here..........

 

[sriddle1]

Want move the tractor pry up the bucket and slip a rope, cable, chain under it and attach to the front of the frame. When you pull the cable tightens and lifts the bucket.

Egon, THANKS......Understood, rain forecasted for the next (3) Days and now that I'm on my way to resolving (With Z5's help and the Shop Manual coming) no need to move unless all else fails and JD has to pick up (Hope Not).............

 

[sriddle1]

Simple relays can be tested reasonably easy. Time delay could also be tested, but I'd have to look more closely at exactly how... Simple in theory, where to put power to the coil and where to measure with an ohm meter to determine proper operation is where the questions come into play.

Edit: swapping relays (starter with fuel, for example) would give you an easy test port...

dieselcrawler,

I like the clean Plug & Play Approach by remove/replace (R/R) both the K1 Start and K2 Fuel Relay while I'm cleaning up the Critter Cavity then see what happens. Looking at the Wiring Diagram K1 Start Relay feeds A1 Time Delay Control Module that feeds back to the K2 Fuel Relay, all interconnected. $250.00 is my break even point before JD would even open the hood...........Guess I'll order those today from Green Parts store, probably arrive right around the shop Manual on CD.

 

[sriddle1]

dieselcrawler, zebrafive,

Still waiting for the K1 Start and K2 Fuel Relays (slow shipping I guess)...........I've attached a PIC of the (2) Relays hanging front/rear & left in the opening. Now that I can see what's going on, looks to be a simple (yea right) remove/replace action. Zooming-in on the PIC appears the K1 Start Relay might be to the rear, I believe I see Wires 605 Blk/Red, 700 Blk/Wht, etc.

Noticed something a bit different after cleaning out the cavity, went back and took voltage measurements to the Solenoid still using Jumpers. The Pull-In measured 10V for 2 seconds then dropped to 6V steady, hadn't noticed that before, in the past read 10V for 2 seconds then dropped to zero. I'll check again today.

Zebrafive, what is the function of the Relay since I'm outside my knowledge space. Also, when I take voltage measurements on the Solenoid Pull-In wires, what's making the click noise associated with the voltage drop, the relay or the A1 Time Delay Module. It will be interesting to see if the new relays correct the issue or I'll be ordering that $213.00 A1 Module, still far better than the JD Dealership Meter Running.

 

[Zebrafive]

dieselcrawler, zebrafive,

Still waiting for the K1 Start and K2 Fuel Relays (slow shipping I guess)...........I've attached a PIC of the (2) Relays hanging front/rear & left in the opening. Now that I can see what's going on, looks to be a simple (yea right) remove/replace action. Zooming-in on the PIC appears the K1 Start Relay might be to the rear, I believe I see Wires 605 Blk/Red, 700 Blk/Wht, etc.

Noticed something a bit different after cleaning out the cavity, went back and took voltage measurements to the Solenoid still using Jumpers. The Pull-In measured 10V for 2 seconds then dropped to 6V steady, hadn't noticed that before, in the past read 10V for 2 seconds then dropped to zero. I'll check again today.

Zebrafive, what is the function of the Relay since I'm outside my knowledge space. Also, when I take voltage measurements on the Solenoid Pull-In wires, what's making the click noise associated with the voltage drop, the relay or the A1 Time Delay Module. It will be interesting to see if the new relays correct the issue or I'll be ordering that $213.00 A1 Module, still far better than the JD Dealership Meter Running.

The time delay module sends the initial pull in voltage to the FS, then the relay (when activated by TDM) continues to provide the voltage to the pull in coil of the FS. Voltage to the relay comes from the white/black 451 wire (Key in RUN) The TDM activates the relay with green/white 655 12 volts and lt green 658 which the TDM grounds.

I am not sure if the clicking is from the relay or TDM Possibly the voltage from the TDM is not enough to activate the relay? Hence it clicks?

You might try cleaning all the connector's terminals to the relay, FS, and TDM. Loose/corroded/dirty terminals could be causing a voltage drop.