# Ford 3930 Wont Turn Over



## jgriswol538802 (Feb 24, 2015)

Ford 3930 with 655 hours. Recently noticed that the gas gauge and temperature gauge were not working, but everything else continued to work. I suspected that the wires may have been chewed by mice since I had seen a mouse run out of the tractor when it was started.

Last week I tried to start the tractor and it would not turn over at all. I did have dash lights and the headlights would come on. I tried jumpstarting but it still wouldn't turn over. The battery read less than twelve volts and was seven years old so I replaced it. Still no difference. I also verified that the safety switches are working at the switch.

I pulled the instrument cluster and sure enough there are several wires that are chewed in two.

1) Is there a wire going to the instrument cluster that would cause it not to turn over? Does the wiring for the safety switch go through the cluster?

2) How do you get the steering column, forward/reverse lever, and the throttle lever off in order to remove the body to have room to rewire and check the other wires?

3) Can I jump the starter solenoid to see if that will make the motor turn over? If so, how? 

4) Any other suggestions of what to check?

5) How to protect it from mice in the future?

Thanks for any help.


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## harry16 (Dec 8, 2011)

Hello jgriswol538802,

Welcome to the Ford/New Holland Tractor Forum. My response to your questions:

Note: I deal with older Ford tractors, so some of my answers may not apply. 

1) Is there a wire going to the instrument cluster that would cause it not to turn over? Does the wiring for the safety switch go through the cluster?

Answer: No. Not to my knowledge. See post by *fedup* below.

2) How do you get the steering column, forward/reverse lever, and the throttle lever off in order to remove the body to have room to rewire and check the other wires?

Answer: I assumed that you do not have a cab on your tractor. 

For the forward / reverse shift lever, It appears to me that you have to remove pin #11 and circlip #12. You may see a better approach. See shuttle shift diagram.

For the throttle control, It appears to me that you have to remove bolt & nut #13 & #14. Again, you may see a better approach. See throttle controls diagram. 

For the steering wheel, you will have to remove the center nut, spray with penetrating oil, let it soak. Then put hands at the 3 and 9 o'clock positions and pull upward rocking side to side. If that doesn't work, try hands at 6 and 12 o'clock positions and rock forward and aft while pulling. If neither works, lets discuss again. Ultradog has made a pulling tool that you might consider. 

3) Can I jump the starter solenoid to see if that will make the motor turn over? If so, how? 

Answer: Yes. Make certain the transmission is in neutral. Refer to post by *fedup* below. 

4) Any other suggestions of what to check?

Answer: Get the instrument cowling lifted up where you can work on the wire damage, and I think you will solve your problems. 

5) How to protect it from mice in the future?

Answer: Put out some rat/mice cubes and maintain a steady supply for them. Make sure your dog/cat cannot get to them. It's been a bad year for rats and mice for me as well.


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## BigT (Sep 15, 2014)

Some of these steering wheels don't come off so easily. And a puller will damage the plastic on the underside of the steering wheel. 

If it won't come off by pulling and rocking, try this approach: Position the center nut so that it's flush with the end of the shaft (protecting the threads). Spray with penetrant and let it soak. Have one guy pull upwards on the steering wheel, rocking it, while a second guy hits the nut with a BFH.


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## Fedup (Feb 25, 2014)

Most 30 series tractors have a start relay on the firewall behind/above the battery. The start signal from the key switch (usually a white wire with red tracer) should go to one pin on this relay, and from another pin down to the starter. As I recall the start wire also has a small jumper to one of the coil circuit pins of the relay. The ground for the coil circuit goes through the neutral switch, then through the pto switch, then to ground. The wiring between the neutral and pto switches is run through a steel tube along the left side of the transmission shift cover and has been known to become damaged.


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## harry16 (Dec 8, 2011)

See item #33 on attached diagram. I believe this is the relay that *fedup* is referring to. In the older Fords, the start wiring goes from the keyswitch though the transmission (and PTO safety switch if applicable) to the starter solenoid. 

Question for *Fedup* - How do we jumper the starter on a 3930 to get the engine running if the starter wiring is screwed up?


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## Fedup (Feb 25, 2014)

*Jump the starter*

Does the tractor have the relay mentioned? If so, then unplug the harness from the relay and locate the two larger wires(usually 12 or 14 gauge, white/red). One comes from key switch start terminal, the other goes to starter solenoid. A short jumper wire (with standard male spade terminals if you have them) inserted into the harness plug in place of the relay will effectively bypass the safety circuit entirely. If the key switch itself or it's related wiring is your problem, then a longer jumper wire plugged into the "relay to solenoid" wire at the harness connector and touched to battery positive should make the starter crank. 
And no, I do NOT need to hear from Safety Sam and/or the safety police. I ASSUME if you're smart enough to follow simple instructions you're also smart enough to find neutral before you try this.


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## jgriswol538802 (Feb 24, 2015)

Thanks for the replies. I Have been sick for the past week and am still under the weather so I haven't gotten back to it yet. As soon as I am able to get back outside I will try your suggestions. 

The dealer quoted $495 for the instrument cluster wiring harness so I will hope that I can just patch the wires.

Thanks again


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## jgriswol538802 (Feb 24, 2015)

*More Info on 3930 Won't Start*

I am still not able to really get outside for any length of time but did discover a couple of things.

I can reach several of the wires to splice as they are long enough that I can reach inside the cowl and still get a good connection. Two of the wires are only about an inch long where they come out of the wiring harness. I don't think I can get to those without removing the body. I didn't have any luck getting the steering wheel nut loose so far. I will get an impact wrench and try again. I wonder if I can lift the body up enough without removing the wheel to get the harness up where I can work on it.

It does have the start relay you referenced. It plugs into the fuse block. I unplugged it and it has two small blades and two large blades. Is this where you are suggesting to jumper , in the block, or unplugging the wired from the back of the block.

The safety switches and wiring are good up to the point they go up into the body.

I did find one 5 Amp fuse blown and have not replaced it yet. The symbol for that position in the fuse block looks like a book ( no lettering just the symbol ). Any idea what that would be .

Should I be able to hear the injector pump when I turn the key to the on position?
( I don't hear anything ) Is there just one wire to the pump and should it have voltage on it when the key is on.

When I turn the key on there is no change on a voltmeter connected across the battery, but if I turn the key to the start position the battery starts discharging.

I know these are kind of random facts . I just haven't the energy to go at it for any length of time.


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## Fedup (Feb 25, 2014)

The large pins on the start relay would be the ones to connect with a jumper, but it will only be effective if power is present to one of them with keyswitch in start. The voltage drop when in start position indicates power is going somewhere. Could be to the thermostart(manifold heater) which can be energized while cranking. If that's what's causing the voltage drop it should change if you unplug the wire from the heater element and test again. It can also mean you're actually getting start signal to the starter but a problem there is causing the starter to not function. 
Yes, there should be 12v to the shut off solenoid on the pump both in the run and start position, and no you probably won't hear it click. Use a meter or testlight to check it. 
Not sure what to think about the fuse other than replace it and see what changes.


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## jgriswol538802 (Feb 24, 2015)

*Ford 3930 Won't turn over*

Thanks Fedup for the help.

I removed the relay and checked for voltage on the fuse block with the key in the start position.

On one side of the small blades ( which I assume are the signal part of the relay ) when I turn the key to start I read about 5 volts from battery negative to the fuse block.

On one side of the large blades when I turn the key to the start position I read 12.5 volts.

I tested the relay by applying 12 volts across the signal side and reading continuity from large blade to large blade. I can also hear the relay making.

I put a jumper in the fuse block from one large blade to the other and was able to crank the tractor by turning the key to the start position. It cranked and ran with the jumper in place.

Am I right in thinking that the 5 volts to the signal side of the relay is insufficient to activate the relay? Is the 5 volts likely a result of one of the damaged wires, a bad ignition switch, a bad ground, or something else? 

I have not rewired the bad wires yet as I have not been up to removing the body just yet.

Thanks again.


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## Fedup (Feb 25, 2014)

I think the large blade terminal with 12.5v should have a small gauge jumper wire behind the scenes that connects directly to the terminal where you read the 5v. They should read the same. Hopefully you can remove the fuse block and have enough wire to turn it around to view it from the back side and see what's going on. The other small terminal should lead to ground when both the neutral and PTO switches are closed.


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