# diode block testing



## charley56 (Oct 8, 2020)

I have a diode block #RE153894, {9-pin relay} does anyone know how to get the schematics on this relay. Or can anyone tell me how to bench test. This is out of 2000 John Deere 4200 tractor. I am having problems with the fuel shutoff solenoid. I can remove the solenoid and start engine (runs fine) but have to reinstall solenoid to kill engine. All other 5pin relays test out fine, I am not getting the plunger on the shutoff solenoid to kick in when I turn on the key switch. Oh and yes the thermistor is testing ok.


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## MCF (Jan 12, 2018)

charley56: I don’t have an answer for you but I keep burning out the thermister on my 4200. Install a new one, starts up two or three times and goes bad again. Can you tell me where the solenoid is located? I did GI d one thread indicating solenoid may get gummed up and not operate properly pulling to much current and blowing the thermistor. Highpockets


charley56 said:


> I have a diode block #RE153894, {9-pin relay} does anyone know how to get the schematics on this relay. Or can anyone tell me how to bench test. This is out of 2000 John Deere 4200 tractor. I am having problems with the fuel shutoff solenoid. I can remove the solenoid and start engine (runs fine) but have to reinstall solenoid to kill engine. All other 5pin relays test out fine, I am not getting the plunger on the shutoff solenoid to kick in when I turn on the key switch. Oh and yes the thermistor is testing ok.


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## charley56 (Oct 8, 2020)

MCF said:


> charley56: I don’t have an answer for you but I keep burning out the thermister on my 4200. Install a new one, starts up two or three times and goes bad again. Can you tell me where the solenoid is located? I did GI d one thread indicating solenoid may get gummed up and not operate properly pulling to much current and blowing the thermistor. Highpockets


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## charley56 (Oct 8, 2020)

not sure if I'm doing this right, but if you look beside the fuel filter you should see the fuel solenoid. remove the bolt holding the fuel filter and then remove the bracket holding the fuel filter. there are two bolts holding the fuel solenoid in place. remove and solenoid will slide out. you can start an run engine without the solenoid, however to kill the engine you either have to insert the solenoid into the hole ( with ignition switch in off position) or stick something in the hole and push the button in to kill engine, I use my finger though (not recommended) I replaced the thermistor by extending the wires (where the thermistor was) and installed a push button in its place. to start the engine I push the button start the engine and left off the button. it only energizes the solenoid long enough to start engine.


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## MCF (Jan 12, 2018)

charley56 said:


> not sure if I'm doing this right, but if you look beside the fuel filter you should see the fuel solenoid. remove the bolt holding the fuel filter and then remove the bracket holding the fuel filter. there are two bolts holding the fuel solenoid in place. remove and solenoid will slide out. you can start an run engine without the solenoid, however to kill the engine you either have to insert the solenoid into the hole ( with ignition switch in off position) or stick something in the hole and push the button in to kill engine, I use my finger though (not recommended) I replaced the thermistor by extending the wires (where the thermistor was) and installed a push button in its place. to start the engine I push the button start the engine and left off the button. it only energizes the solenoid long enough to start engine.


Charley56. Thank you for the reply. You were right on! I unbolted the fuel filter assembly and removed the steel divider to access the solenoid. Installed a new solenoid and thermistor but tractor will not start. 
It starts right up with solenoid removed so I still have an electrical issue. Going to replace the K3 shutoff relay next. Hope this solves the problem. Highpockets.


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