How to test B1700 ignition switch

North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
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Sandpoint, ID
Let me see if I can clarify things?

There are two signals that the tractor needs to start and run.
Signal 1: Being a signal to the hold side of the fuel stop solenoid constant feed from the red / black wire to the solenoid.
Signal 2: Being a signal to the starter solenoid to engage (black/white wire) and this passes a signal on to the fuel stop solenoid via a second connection off the back of the starter which is a white wire, to pull in the fuel stop solenoid on cranking.

If the tractor will start with the key then die when you let off the key from crank then you have either no signal going to the red / black, a blown 5 amp fuse, or a bad solenoid, verify this by putting a test light on the red/black wire at the fuel stop solenoid and turning the key to run.

Now if it will not crank with the key then something is stopping the signal from getting to the starter solenoid, you need to verify where the break is by following the wire and testing it at all locations.
It travels from the key switch threw several safety switches then to the starter solenoid.

 

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tbronson

Member

Equipment
B1700 HSD w/ LA302 FEL, B48CA rototiller
Jul 1, 2016
61
0
6
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if it will not crank with the key then something is stopping the signal from getting to the starter solenoid, you need to verify where the break is by following the wire and testing it at all locations.
It travels from the key switch threw several safety switches then to the starter solenoid.
Thanks! I will attempt to follow the wiring today.

QUESTION: Is there some point with checking the wiring where I won't be able to get at it without major taking apart of the tractor? And is the schematic for the B1700 or a general guide?

NOTE: Haha, this thread is getting a little complicated, although I'm following. That's why I started by focusing on the key switch first. My plan was to break things down into separate threads. :)

SUMMARY:

1. Key switch at all positions gets no response. Previously, it sometimes took several tries to start, but usually dash lights would always go on and the fuel needle would climb. Now, there is no response at all.

2. Tested key switch with multimeter, and there is continuity for all positions corresponding to the key position map (supplied in an earlier post).

3. Jumpstarting by shorting the solenoid (big post with battery cable to little tab) works easily (but engine stops when connection is removed).

4. Apparently no voltage when key at START and tester grounded and touching the solenoid small metal tab (with the wire that connects to it in place).

NOW I'm gonna try tracing the wiring!!!

PS: This is a working tractor for a small market garden. I'm really tight on repair funds and trying to fix by learning DIY, so...thanks!! Weeds are growing, beds need tilling,...race against time! :)
 

North Idaho Wolfman

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Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,306
4,856
113
Sandpoint, ID
Thanks! I will attempt to follow the wiring today.

QUESTION: Is there some point with checking the wiring where I won't be able to get at it without major taking apart of the tractor? And is the schematic for the B1700 or a general guide?

NOTE: Haha, this thread is getting a little complicated, although I'm following. That's why I started by focusing on the key switch first. My plan was to break things down into separate threads. :)

SUMMARY:

1. Key switch at all positions gets no response. Previously, it sometimes took several tries to start, but usually dash lights would always go on and the fuel needle would climb. Now, there is no response at all.

2. Tested key switch with multimeter, and there is continuity for all positions corresponding to the key position map (supplied in an earlier post).

3. Jumpstarting by shorting the solenoid (big post with battery cable to little tab) works easily (but engine stops when connection is removed).

4. Apparently no voltage when key at START and tester grounded and touching the solenoid small metal tab (with the wire that connects to it in place).

NOW I'm gonna try tracing the wiring!!!

PS: This is a working tractor for a small market garden. I'm really tight on repair funds and trying to fix by learning DIY, so...thanks!! Weeds are growing, beds need tilling,...race against time! :)
Test light onto the Large terminal, positive power.
Test light onto main wire into switch, positive power.
Test light on any of the outputs relative to key position, positive power.

If your not getting all of the above then you have a power feed issue.
 

tbronson

Member

Equipment
B1700 HSD w/ LA302 FEL, B48CA rototiller
Jul 1, 2016
61
0
6
Ontario
Test light onto the Large terminal, positive power.
Test light onto main wire into switch, positive power.
Test light on any of the outputs relative to key position, positive power.

If your not getting all of the above then you have a power feed issue.
I'll check those tomorrow. Thanks.

What is a power feed issue? At what point do I give up on DIY and prepare to spend?

ALSO: After I jumpstart it, why doesn't it keep running with the key at RUN?
 
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D2Cat

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L305DT, B7100HST, TG1860, TG1860D, L4240
Mar 27, 2014
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40 miles south of Kansas City
In post #13 you said this, "QUESTION: I can easily jumpstart it, but as soon as I remove the screwdriver, it immediately runs down and stops. Same when switch is at Off and at Run. How can I get it to keep running?

Now go back to post #21. There is the explanation of the start/run solenoid and how to test it. If you have already removed the negative (ground) wire that comes off of the battery and goes to the tractor frame, and scraped all the rust and paint of the bolt and reattached the ground wire.....go through post #21 and follow the details. You will then know if you are getting 12 volts to the solenoid to start and then to stay running. There are two parts to that solenoid, as explained there.

You can fix this problem but you need to follow through in detail and report the results....or you will have to take to someone else.
 

tbronson

Member

Equipment
B1700 HSD w/ LA302 FEL, B48CA rototiller
Jul 1, 2016
61
0
6
Ontario
It's fixed! I found the problem literally a minute before phoning for the industrial equipment/tractor mechanic ($80 for the service call-$80/hr). Thanks for all the help, I learned a lot in this thread.

The problem was just a fuse, a 30A box fuse that was right in front of me all the time, near the starter. I'd even unplugged and replugged it more than once.

Problem is, I didn't know it was a fuse. Then, in my last look around before calling the mechanic, I noticed the 30A in raised letters on the clear plastic top of the fuse -- not easy to see, because it's not printed, just clear plastic. Once I saw that, I took it out and checked it. 30 minutes later, after a trip to the hardware store: back in business.

SUGGESTION: When helping the inexperienced, don't underestimate how little they know. :) I only recognized those flat fuses that're in the fuse box, never seen a box fuse (no-one has a clear name for it) before. Being told what the various fuses look like would've cleared things up in minutes! :)

The advice here kept me on it. THANKS!!!
 

Be_The_1700

New member

Equipment
B1700
Jul 5, 2022
2
1
3
NH
Hi, I'm new to forum, working on my Dad's B1700 which I inherited maintenance of.

I have similar starting issue. Would start on 4th turn of switch until neighbor borrowed it. Probably would have gone bad with me driving it also.

Diagnosis steps:
  • Brand new battery a month ago. Battery still measures 12.5V
  • Starter measures 12.5V at big lug
    • Tiny lug on starter goes to 0.02V when switch goes, same with white smaller lug.
    • Had a new starter my dad had bought, installed that, no difference.
  • Switch has 12.5 V coming up 2 of 4 wires. Based on diagram one switches in the glow plug and other goes to starter
    • Switch switches power from big red lug to big black lug when switched
    • indicator lights work, guess that means its not the starter switch
  • Safety position switches checked.
    • One under seat was hot wired by someone, seemed to still work
    • second - Is there one right by starter? If so, the plug was loaded with sand. Cleaned it out, still no starting
    • Third - found one hanging near bottom of tractor under seat on left. Will try and figure out where it goes or hot wire it tomorrow