Deere 950 Help with starter assist relay

[hondo964]

I have read quite a bit on TBN about a fairly common problem on the 50 series Deere tractors (750, 850, 950, 1050) - and many other tractors - of a voltage drop to the solenoid/starter due to age of wiring etc. I am near sure I have this issue with my 950 and the frustrating clunk. However, I need some guidance on how to proceed since I am not skilled in this area. Here are my questions:

1. How do I test for a voltage drop at the solenoid? From reading other posts, it seems like I take a voltage meter, dial it to 15 or 20 and put the 2 probes on the positive and negative posts of the battery for the first voltage reading. Then, I get someone to turn the key to start the tractor while I put the red probe on say the tip of the big lug/post of the solenoid?? Where do I place the negative probe? Do i unplug the wire that I think is coming from the ignition switch thru the neutral start switch - and put the negative on the tip of that wire OR do I try to place it on the lug of what I think is the negative post of the solenoid OR do I put it on the tractor frame?

Here's what I see:

There are 2 wire ends that terminate together at that big lug/post of the solenoid. I believe one is straight from the battery (thick cable) and one is from the ignition switch (includes fusible links). Does this sound right?

There is another wire that comes into the solenoid by itself. I believe that's the one that comes from the ignition and through the neutral start switch. Does that sound right? It is a very odd shaped end - it's a flat plug embedded in a fancy connector housing. Can't figure out why they wouldn't just have a post you could put a circle end/more universal connector on.

(If anyone has a wiring diagram for a 950 with a serial number over 20000, please let me know).

2. It looks like the other big lug of the solenoid tight against the engine block has a wire? inside a rubber tube that leads up into the bottom starter.

3. Does the solenoid have a negative wire somewhere?

Thanks for the insights/help!

 

[Barry 1]

Can you figure this out? The starter wire from the key(that goes to bottom of starter solenoid) is cut and attached to small terminal(I just had that rubber terminal). Big post on left is for battery power off of starter.Big post on right goes back down to starter solenoid. There is 2 bolt holes on manifold to mount the old Ford solenoid(ebay) (just drill holes a little more on solenoid) There are other ways to do this but this was simple.No more click click click !

 

[rScotty]

I have read quite a bit on TBN about a fairly common problem on the 50 series Deere tractors (750, 850, 950, 1050) - and many other tractors - of a voltage drop to the solenoid/starter due to age of wiring etc. I am near sure I have this issue with my 950 and the frustrating clunk. However, I need some guidance on how to proceed since I am not skilled in this area. Here are my questions:

1. How do I test for a voltage drop at the solenoid? From reading other posts, it seems like I take a voltage meter, dial it to 15 or 20 and put the 2 probes on the positive and negative posts of the battery for the first voltage reading. Then, I get someone to turn the key to start the tractor while I put the red probe on say the tip of the big lug/post of the solenoid?? Where do I place the negative probe? Do i unplug the wire that I think is coming from the ignition switch thru the neutral start switch - and put the negative on the tip of that wire OR do I try to place it on the lug of what I think is the negative post of the solenoid OR do I put it on the tractor frame?

Here's what I see:

There are 2 wire ends that terminate together at that big lug/post of the solenoid. I believe one is straight from the battery (thick cable) and one is from the ignition switch (includes fusible links). Does this sound right?

There is another wire that comes into the solenoid by itself. I believe that's the one that comes from the ignition and through the neutral start switch. Does that sound right? It is a very odd shaped end - it's a flat plug embedded in a fancy connector housing. Can't figure out why they wouldn't just have a post you could put a circle end/more universal connector on.

(If anyone has a wiring diagram for a 950 with a serial number over 20000, please let me know).

2. It looks like the other big lug of the solenoid tight against the engine block has a wire? inside a rubber tube that leads up into the bottom starter.

3. Does the solenoid have a negative wire somewhere?

Thanks for the insights/help!

I can answer the questions, but because you are getting a clunk, there may be a faster way to test the starter. You will need a set of jumper cables and might need a known good 12 volt battery out of any vehicle. But first just use cables....

1. Using the big spring clamps on the black battery cable, connect that cable from the negative (-) terminal of the tractor battery to a clean bare metal place on the metal frame of the tractor or to the engine block. Your battery should have a cable like that already, but it is common for that battery wire to be corroded on the ends where you cannot see them easily (causing a voltage drop). So we are using the black jumper cable to make sure we have a good connection from the battery negative terminal to the frame.

2. Put the tractor in Neutral, turn OFF the PTO, and set the throttle at the lowest setting. We don't care about the ignition switch right now. But if you have a fuel tap turn it off too.
3. Double check everything in #2. This tractor is going to try to start and take off by itself. So make sure it cannot.

4. Look at the starter. See the large wire running from the solenoid to the rubber boot on the starter? Is shows clearly in the photo in post #2. Peel back that rubber boot so that the heavy wire connection is exposed on the starter. It won't shock you, but wear gloves if you are worried.

5. Now take your other jumper cable - the red one - and being real careful to keep the far away from anything, take the other end and clamp it to the positive terminal of the battery. Do NOT let that clamp touch the frame or the tractor or it will spark. Connect it to the + terminal of the battery only and wiggle it to make sure all is secure. You don't want it coming off because if all goes well, the starter motor is about to try to start the tractor. The red cable is now connected at one end to the + of the battery and can now carry power. Again, do NOT let the free end of the red battery cable touch anything or it will spark like an arc welder.

6. Here goes the test: Standing as far away from the tractor as seems prudent, touch the free end of that red battery cable to that connector on the starter you exposed when you peeled back the black rubber cap.
Be prepared for the starter to turn !! I And LOUDLY, Too. THE MOTOR MIGHT EVEN START FOR A MOMENT. Don't panic ! If it starts, make it stop however you normally stop it.

7. If the test shows that the starter turns then the starter is good. Carefully disconnect both of your jumper cables from the battery and put them away. If the starter turned, you either have bad battery cables or a bad solenoid. Replace the two battery cables and the solenoid. The starter is good.

good luck,
rScotty

 

[WranglerX]

Can you figure this out? The starter wire from the key(that goes to bottom of starter solenoid) is cut and attached to small terminal(I just had that rubber terminal). Big post on left is for battery power off of starter.Big post on right goes back down to starter solenoid. There is 2 bolt holes on manifold to mount the old Ford solenoid(ebay) (just drill holes a little more on solenoid) There are other ways to do this but this was simple.No more click click click !
View attachment 811771View attachment 811772View attachment 811773

Looks like a "hot start" relay wiring we use on VW aircooled starters...

 

[rScotty]

Looks like a "hot start" relay wiring we use on VW aircooled starters...

Nice drawing. At first I though, "What?"... and then after some thought realized what I was seeing was an accessory or after market that would be necessary when the ignition switch is not capable of handling normal starter solenoid amperage ... and yes, hot engine compartments do sometimes take more amperage to run the starter. Just like cold ones do, but for a different reason.

However, the traditional simpler way to do that wiring would be to use a more expensive ignition switch with good copper contacts in the first place, changing to using a heavier #10 wire for wire 85, and connecting that wire it directly to terminal 60 on the solenoid. That way the extra fuse and relay can be eliminated and electrically it is doing the same thing....but with less monkey motion.
Most all older cars, trucks, and tractors were made that simpler way.

rScotty

 

[hondo964]

Can you figure this out? The starter wire from the key(that goes to bottom of starter solenoid) is cut and attached to small terminal(I just had that rubber terminal). Big post on left is for battery power off of starter.Big post on right goes back down to starter solenoid. There is 2 bolt holes on manifold to mount the old Ford solenoid(ebay) (just drill holes a little more on solenoid) There are other ways to do this but this was simple.No more click click click !
View attachment 811771View attachment 811772View attachment 811773

Barry,

Thanks for this! In trying to figure your photos out, i have 3 questions:

In talking about the original setup, when you say "the starter wire from the key that goes to the bottom of the solenoid" - do you mean the small wire that has a flat connector and plugs into the solenoid by itself? (OR the small wire on the solenoid that is on the same lug as the big wire from the battery)?

In talking about the modified setup, when you say "the big post on the right goes back down to the starter solenoid" - where exactly on the starter solenoid?

There are 2 small wires on the original set up that I'm trying to trace out in your photos..

My 950 doesn't have the holes on the manifold available because of the air intake. I am guessing that since your 1050 has the turbocharger, those holes were available to you. Without those holes, any thoughts on a mounting location?

 

[hondo964]

I can answer the questions, but because you are getting a clunk, there may be a faster way to test the starter. You will need a set of jumper cables and might need a known good 12 volt battery out of any vehicle. But first just use cables....

1. Using the big spring clamps on the black battery cable, connect that cable from the negative (-) terminal of the tractor battery to a clean bare metal place on the metal frame of the tractor or to the engine block. Your battery should have a cable like that already, but it is common for that battery wire to be corroded on the ends where you cannot see them easily (causing a voltage drop). So we are using the black jumper cable to make sure we have a good connection from the battery negative terminal to the frame.

2. Put the tractor in Neutral, turn OFF the PTO, and set the throttle at the lowest setting. We don't care about the ignition switch right now. But if you have a fuel tap turn it off too.
3. Double check everything in #2. This tractor is going to try to start and take off by itself. So make sure it cannot.

4. Look at the starter. See the large wire running from the solenoid to the rubber boot on the starter? Is shows clearly in the photo in post #2. Peel back that rubber boot so that the heavy wire connection is exposed on the starter. It won't shock you, but wear gloves if you are worried.

5. Now take your other jumper cable - the red one - and being real careful to keep the far away from anything, take the other end and clamp it to the positive terminal of the battery. Do NOT let that clamp touch the frame or the tractor or it will spark. Connect it to the + terminal of the battery only and wiggle it to make sure all is secure. You don't want it coming off because if all goes well, the starter motor is about to try to start the tractor. The red cable is now connected at one end to the + of the battery and can now carry power. Again, do NOT let the free end of the red battery cable touch anything or it will spark like an arc welder.

6. Here goes the test: Standing as far away from the tractor as seems prudent, touch the free end of that red battery cable to that connector on the starter you exposed when you peeled back the black rubber cap.
Be prepared for the starter to turn !! I And LOUDLY, Too. THE MOTOR MIGHT EVEN START FOR A MOMENT. Don't panic ! If it starts, make it stop however you normally stop it.

7. If the test shows that the starter turns then the starter is good. Carefully disconnect both of your jumper cables from the battery and put them away. If the starter turned, you either have bad battery cables or a bad solenoid. Replace the two battery cables and the solenoid. The starter is good.

good luck,
rScotty

rScotty,

Thanks for this; the starter is good. I described the problem as a "clunk" but one could also call it a loud "click" when you turn the key to start. It is intermittent and can be a pain - so I was trying to confirm a voltage drop at the solenoid and I wasn't absolutely sure where to put the tester ends.

(As I mentioned, this is a very common problem, especially as tractors age and I was also seeing with lawn and garden tractors and I thought I'd try to confirm it here. The solution that Barry shows is most common but I don't understand electrical enough to understand how that solution works - I figure it is directing more current more quickly to the solenoid so that the solenoid doesn't have to wait for the current to be received after the long circuit involving neutral switches and the like).

 

[Barry 1]

You cut the wire with the flat plug that goes from the key to the starter solenoid.From the key goes to the terminal where I attached the rubber plug. The cut wire with the flat plug goes on the right terminal of the ford solenoid.You could drill a couple of holes and mount the solenoid to the right of the starter below the fuel tank ?Leave every thing else alone.