Can relays be tested?....John Deere 2320 electrical issues!!!

[bumpyrider]

Don't forget that service manual, too! They're well worth the money if you plan on keeping the tractor...
Since you said the glow plug light was always on, one quick test you could do is (once you've located the glow plug relay) have someone turn the ignition on (not start, just on) while you listen and maybe touch the relay, if it's safe (I don't where anything is on your rig). The relay should click when the ignition is turned on, and after a short time the relay should click again after the glow plug has heated up. If you don't hear or feel the relay change at all, you could be on the right track.
Without the electrical schematic, I'm totally guessing here, but the relay is probably operated by a timer, and the glow plug comes off of one set of contacts, the indicator light off of another set. If you can measure the voltage on the coil (sometimes marked A1/A2 on the terminals) you should see 12volts there only during the normal glow plug warm-up time. If the 12volts on the coil does not go away, your problem is before the relay.
Like Tom said, the best thing is to get the manual and start following the troubleshooting charts. The problem might not be here at all and I'm just "leading you down the garden path..."

 

[kyles974]

Don't forget that service manual, too! They're well worth the money if you plan on keeping the tractor...
Since you said the glow plug light was always on, one quick test you could do is (once you've located the glow plug relay) have someone turn the ignition on (not start, just on) while you listen and maybe touch the relay, if it's safe (I don't where anything is on your rig). The relay should click when the ignition is turned on, and after a short time the relay should click again after the glow plug has heated up. If you don't hear or feel the relay change at all, you could be on the right track.
Without the electrical schematic, I'm totally guessing here, but the relay is probably operated by a timer, and the glow plug comes off of one set of contacts, the indicator light off of another set. If you can measure the voltage on the coil (sometimes marked A1/A2 on the terminals) you should see 12volts there only during the normal glow plug warm-up time. If the 12volts on the coil does not go away, your problem is before the relay.
Like Tom said, the best thing is to get the manual and start following the troubleshooting charts. The problem might not be here at all and I'm just "leading you down the garden path..."

I will GLADLY take any advice....even if it leads me in wrong direction. ...lol
As a said....my expertise in this leval of electronics are slim.

Also...I do have the service manual. Found one used one on the bay a while back. But...not sure if any has tried to look up something in these......wow! It's almost another laungue. Kinda frustrating. But I do plan on opening the book back up.
Wanted to try my luck out here first...since most seem to be on the "same page" in the words of speaking.
In fact....today...was talking with my dad o phone....told him about the service book...he lmao....almost...roflmao at me because they way I said it.

Last time I looked thew the book I was like wtf! ...lol

Ok...I just opened the service book....what would you think you could find relays under? Relays right? Nope! .....lol
Ok...maybe under electrical system right? Nope again.....
Anyone know what an engineer would call a relay?

 

[bumpyrider]

That little square greasy thingy...

Actually, I did a quick search and found they might refer to it as a 'module'.

Also found a reference to a controller/timer on a different JD, http://www.tractorbynet.com/forums/parts-repairs/281477-john-deere-4100-glow-plug.html

Just thought you might want something to do today!

 

[k0ua]

Relays are just called Relays. Here is how they work.
Let us talk about the simplest relay, one that has a single set of contacts that only go in on direction to make an electrical connection when energized. We call this a SPST relay. It is Single Pole, Single Throw.

What that means is there is just a single set of contacts (the single pole) and it just moves in one direction when energized and does not make any connection when it is relaxed. So what causes the single pole to move? All relays have at least one coil. A coil is just what it sounds like a coil of very small wire. If we apply 12 volts on one end of this coil and ground on the other, electrical current will flow in this coil of wire.

This coil of wire has resistance that you can measure on an ohm meter, it will be fairly low, but not 0 ohms. So what happens when we pass this current thru this coil of wire? A magnetic field is generated in this coil of wire when current is passed thru it.

This magnetic filed attracts a piece of steel called the "pole piece" which has the movable contact of this set of contacts we talked about, towards the non moveable contact until they touch. These contacts have leads attached to them and brought out side of the relay enclosure. As long as the coil is energized by the electrical current flow these contacts will will remain "closed" and making contact with each other. The resistance between the contacts when they are touching together should be near 0 ohms.

So what is the overall point of a relay? Why do we need them? Well they allow small amounts of current to be used in controlling large amounts of current. For instance we could have weak small relay coil current be able to switch on a huge amount of current that would be used to control something like a starter solenoid, or the huge amount of current that glow plugs require.

You could not for instance run the glow plug circuit thru the key switch ( you sure would need an awfully large key switch) but with a relay, you can easily accomplish this with just a tiny current from the key switch to control the glow plug relay whose SPST contacts now control a huge current (in the order of 60 to 70 amps).

So in summation. a simple relay is an electro-mechanical device that a small current passed thru its coil will cause mechanical movement of a set of large current carrying capacity contacts inside the relay to operate much like a large switch.

When the relay is relaxed (not energized) the contacts are "open" in other words infinite ohms, and when the relay is energized the contacts are "shorted" or 0 ohms.

There is more of course, like all subjects electrical, but I hope that this gives you some idea of what relays are and how they work.

 

[kyles974]

That little square greasy thingy...

Actually, I did a quick search and found they might refer to it as a 'module'.

Also found a reference to a controller/timer on a different JD, http://www.tractorbynet.com/forums/parts-repairs/281477-john-deere-4100-glow-plug.html

Just thought you might want something to do today!

Relays are just called Relays. Here is how they work.
Let us talk about the simplest relay, one that has a single set of contacts that only go in on direction to make an electrical connection when energized. We call this a SPST relay. It is Single Pole, Single Throw.

What that means is there is just a single set of contacts (the single pole) and it just moves in one direction when energized and does not make any connection when it is relaxed. So what causes the single pole to move? All relays have at least one coil. A coil is just what it sounds like a coil of very small wire. If we apply 12 volts on one end of this coil and ground on the other, electrical current will flow in this coil of wire.

This coil of wire has resistance that you can measure on an ohm meter, it will be fairly low, but not 0 ohms. So what happens when we pass this current thru this coil of wire? A magnetic field is generated in this coil of wire when current is passed thru it.

This magnetic filed attracts a piece of steel called the "pole piece" which has the movable contact of this set of contacts we talked about, towards the non moveable contact until they touch. These contacts have leads attached to them and brought out side of the relay enclosure. As long as the coil is energized by the electrical current flow these contacts will will remain "closed" and making contact with each other. The resistance between the contacts when they are touching together should be near 0 ohms.

So what is the overall point of a relay? Why do we need them? Well they allow small amounts of current to be used in controlling large amounts of current. For instance we could have weak small relay coil current be able to switch on a huge amount of current that would be used to control something like a starter solenoid, or the huge amount of current that glow plugs require.

You could not for instance run the glow plug circuit thru the key switch ( you sure would need an awfully large key switch) but with a relay, you can easily accomplish this with just a tiny current from the key switch to control the glow plug relay whose SPST contacts now control a huge current (in the order of 60 to 70 amps).

So in summation. a simple relay is an electro-mechanical device that a small current passed thru its coil will cause mechanical movement of a set of large current carrying capacity contacts inside the relay to operate much like a large switch.

When the relay is relaxed (not energized) the contacts are "open" in other words infinite ohms, and when the relay is energized the contacts are "shorted" or 0 ohms.

There is more of course, like all subjects electrical, but I hope that this gives you some idea of what relays are and how they work.

The first quote above.....thank you!! That is great info.
The second.... great info too....learned something. Thank you for taking the time to write all that out for me.


My house was flooded back in April. (Lower half....we been living in upper part that was an addition and sit on blocks...which is kitchen ...living....bath....and one bedroom. .....me...wife....and two girls..5&8.....so been very busy trying to get the damage finally fixed.....been a stressful summer! My closet has been a ccardboard box behind couch in livimg room.....which is filled with boxes of things that made it threw the flood)

Anyhow. ....most of my time has been focusing there. Today I'm taking day off. Goimg to go tinker on the tractor and see what I find. I will post later.

Bit again.....a big thank you to all that has been helpimg along.