John Deere LT160 won't start - seems like no power at all

[HovercraftFullaEels]

Hello,

I've been searching Google a bit and have seen some similar problems to mine, but the few solutions I found haven't worked for me. My LT160 won't start. I turn the key, and get no power; the hour meter doesn't turn on, nothing. So far here's the troubleshooting I've done:

-Made sure the battery has power. My charger shows it is fine.
-Tried unplugging the safety sensors to eliminate them as being bad (seat and parking brake sensors). Tried to start after unplugging each one one a a time - still exact same.
-Used my air compressor to blow out the dust from all electrical connections I could find. Figured it would be good to clean them out and re-seat them.
-My neighbor is a retired mechanic and when I started having this problem in the Fall he suggested it was probably a bad solenoid, since at the time you could jump across it with pliers and it would start. By the end of the year it quit doing that even. I replaced the solenoid but still have the same problem. I can now jump across the solenoid and the engine turns over. You can see fuel going to the engine but it never actually catches and starts. If I pour a little gas in the carb it will catch and start for a second, but as soon as I move the pliers away from the solenoid it dies immediately.
-While I was replacing the solenoid, I also did a full tune-up using the JD maintenance kit (fuel filter, spark plug, air filter, oil, oil filter). Probably doesn't have much to do with this issue, but it should at least eliminate the spark plug as an issue (but does this need gapped? I'm assuming it was done already but I'm not sure).

So at this point I'm thinking it's either the ignition switch or the fusible link wire. I've got these and a couple other items in my cart over at greenpartstore.com, but wanted to check with some more knowledgeable people before pulling the trigger on ordering them.

 

[ILENGINE]

Unplugging the parking brake safety switch may keep it from starting. first question is do you have 12 V to the small wire on the solenoid when the key is turned to start. If not then your problem is some place between the key and the solenoid, which could include safety switches.

 

[HovercraftFullaEels]

I'll give that a look tomorrow after work. I've got a VOM, I just wasn't sure where to start troubleshooting on one of these. Thanks!

 

[HovercraftFullaEels]

Ok, so when I turn the key I have 12v on the battery side of the solenoid (which I assume I should since it's directly attached to the battery), but nothing beyond that. I checked the fusible link cable, both small wires on the solenoid, and the starter side of the solenoid. I tried testing the brake switch but I"m not really sure what I'm looking for and can't seem to find a wiring diagram. Should I just be testing for voltage across the contacts on the connector? With the switch depressed or not?

I found a thread that mentions just unplugging the small wire to eliminate the possibility of it being one of the switches, but which wire am I looking for? The one that attaches to the ignition side post of the solenoid, or one of the other two wires that connects to it? I'll give those a try just to see what happens, but it at least looks like the ignition isn't the problem at this point.

Edit: Tried unplugging all the small wires one at a time from the solenoid. I unplugged each and tried to start it, then plugged it back in when it didn't work. Tried with all of them unhooked and still nothing.

 

[Rivets]

Try this troubleshooting procedure.



Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.

 

[HovercraftFullaEels]

Excellent, I should be able to give this a try tomorrow. I've got a pretty good knowledge of electricity. I had two classes in industrial electricity in college, but that was about 7 years ago and about all I do with a VOM now is test server power supplies occasionally. I figured I'd do ok troubleshooting this if I could just find a wiring diagram to verify that I knew what I was looking at, but the service manual is $100+ on eBay. I'll print this out and go through it thoroughly tomorrow and take notes on everything. If it comes down to it, my brother-in-law is an electrical engineer and he happens to be in town this weekend. If I can't figure it out tomorrow I may be able to get him to stop over and check it out before he leaves on Sunday.

Try this troubleshooting procedure.



Electrical* problems can be very easy or very difficult, depending on four things.
1. * How well you understand basic electricity.
2. *What tools you have and know how to use.
3. *How well you follow directions.
4. *You don't overlook or assume anything and verify everything.

Remember we cannot see what you are doing. *You are our eyes, ears and fingers in solving this problem. *You must be as accurate as you can when you report back. *The two basic tools we will ask you to use are a test light and a multi-meter. *If you have an assistant when going through these tests it would be very helpful. *These steps work the best when done in order, so please don't jump around. *Now let's solve this problem.

First, check the fuse(s), check battery connections for corrosion (clean if necessary) and *voltage - above 12.5 volts should be good.*

Second, check for power from the battery to one of the large terminals on the solenoid. *One of the wires is connected directly to the battery and has power all the time so one of the large terminals should light a test light or show 12 volts on a meter at all times.*

Third, *check for power at the small terminal of the solenoid while depressing the clutch/brake pedal and holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). If your solenoid is a four wire solenoid, check both small wire terminals as one is ground and the other is power from the ignition switch. *If your solenoid is a three wire solenoid, make sure the solenoid body is not corroded where it bolts to the chassis of the mower as this is your ground path back to the battery. *If in doubt, remove the solenoid and clean the mounting area down to bare metal. *If there is no power to the small terminal then your problem is most likely a safety switch, ignition switch or in the wiring.*

Fourth, check for power on the other large terminal of the solenoid while holding the key in the start position (you may need an assistant to sit in the seat to override the safety switch). *If you have power what is the voltage?

Fifth, check for power at the starter while holding the key in the start position (assistant again). *If you have power what is the voltage?

Sixth, check your ground circuit back to the battery.

After you have gone through each of the above steps, let us know what happened when you did each step. *At that point we will have great info to tell you how to proceed. *Remember you are our eyes, ears, and fingers, so please be as accurate as possible.

Be as specific as possible with voltage readings as this will help diagnose your problem quicker. *If you do not know how to perform the above checks, just ask and I will try to guide you through it. *Youtube also has some videos and as you know a picture is worth a thousand words.

 

[HovercraftFullaEels]

I was able to run through this a few minutes ago:

-Hooked up my battery to the charger just to make sure I didn't wear it down by testing the other day. Charger showed fine. All terminals and wires are clean and corrosion free.
-Measured across the battery terminals with my VOM, measured 12.38V.
-Checked from negative battery terminal to the large terminal on the battery side of the solenoid. Measured 12.32V.
-Got nothing beyond that. The solenoid is 4-wire, and got nothing on the starter side large terminal, the purple small wire on the solenoid, or anything on the starter itself (all with the key turned, brake pedal locked in engaged position, and me sitting on the seat).
-I don't see any fuses, except for the fusible link cable that's connected to the battery side large terminal on the solenoid. I'm not 100% sure that is good, but have one on the way that's supposed to arrive today. I'll update the thread if it does to let you know the results of replacing it.
-Checked from the small black cable on the solenoid back to the positive battery terminal. Got 12.28 volts, so it appears the solenoid ground is ok.

It looks like there's a good chance it was the fusible link. I just got the new one in today and started to look at the old one and it fell apart.

Edit: I don't have everything I need to get the fusible link installed tonight, but I'm going to make a trip to Lowes in the morning to pick up the couple things I need. I did try using a pair of alligator clips that I had laying around in its place and got the motor to turn over and start, but it died as soon as I let off the key. After that it was iffy about starting again. The hour meter would flash on and off and it would try to start but wouldn't. I think it's because the wire on the clips is too small and can't carry the current needed to start the mower and keep it running. Once I get the fusible link installed I think that will fix the problem I've been having.

 

[Rivets]

Third step you were testing voltage coming back to the solenoid from the key switch author in the start position. I am assume that you knew to the the unit should have the parking brake on, PTO switch off and unit in neutral. You should have a small wire going from the large terminal you tested in step 2, to the key switch and then when you turn the key switch to start, it should come back to one of the small terminals on the solenoid. The other small terminal on the solenoid should be going to ground.

 

[HovercraftFullaEels]

Yeah, I should have mentioned that. I had the parking brake locked in position, the blades weren't engaged (my deck was actually off altogether, but the lever to engage them was set to "off"), and there's no neutral lever. Mine has a small wire that attaches to the battery side of the solenoid on the large terminal, but that's the fusible link. It attaches to a red wire that comes down from the ignition and looks like it was cut in half for the fusible link to be attached. That red wire then continues on to a big white connector that runs up and attaches to the engine (with I believe a black wire and a white wire from somewhere else). The small wire on the battery side of the solenoid goes to ground, and the small wire on the starter side of the solenoid looks like it runs down and attaches to the parking brake safety switch.

Third step you were testing voltage coming back to the solenoid from the key switch author in the start position. I am assume that you knew to the the unit should have the parking brake on, PTO switch off and unit in neutral. You should have a small wire going from the large terminal you tested in step 2, to the key switch and then when you turn the key switch to start, it should come back to one of the small terminals on the solenoid. The other small terminal on the solenoid should be going to ground.

 

[HovercraftFullaEels]

Replaced the fusible link. Still doesn't start. I'm just going to order every switch on this bloody thing and replace them. If that doesn't work it can become a burnt out lawn sculpture along with the brand new Husqvarna pushmower I bought that stalled out and won't start again.

Yeah, I should have mentioned that. I had the parking brake locked in position, the blades weren't engaged (my deck was actually off altogether, but the lever to engage them was set to "off"), and there's no neutral lever. Mine has a small wire that attaches to the battery side of the solenoid on the large terminal, but that's the fusible link. It attaches to a red wire that comes down from the ignition and looks like it was cut in half for the fusible link to be attached. That red wire then continues on to a big white connector that runs up and attaches to the engine (with I believe a black wire and a white wire from somewhere else). The small wire on the battery side of the solenoid goes to ground, and the small wire on the starter side of the solenoid looks like it runs down and attaches to the parking brake safety switch.