ZD21 Electrical Issue

[Blue]

MY ZD21 (2003 model) won't start or shut down with the key switch. I can start it with a screwdriver at the starter and it runs fine. It won't shut down with the key though. I manually shut it down at the injector pump. I tested the shutdown solenoid and it was bad. Ordered a new one.
All 5 safety switches tested good. The ignition switch tested good. I relocated the battery ground as it had a lot of paint and some minor corrosion on the fastener. I relocated it to a spot on the frame that I was able to grind the paint off to make a good connection. The battery tested good also. After looking at similar threads here I replaced the combination box thinking it was the problem. Still can't start with the key.
Any help is greatly appreciated.

 

[Captain13]

The safety switches may test ok but something may be preventing the micro switch lever from fully operating the switch. On my ZD21 it was the blade engage lever safety switch. Debris had built up on between the silver switch lever and the switch itself causing the switch not to work right (switch thought the blade was always engaged). Once I cleaned that are out, all was well. It’s hard to get to and compressed air didn’t do the trick. Also, the lever was slightly bent and had to be bent back a little to work properly due to the debris build up.

 

[Blue]

I checked and it was ok

 

[Captain13]

Have you checked all the fuses? Go to this post: https://www.orangetractortalks.com/forums/threads/40-amp-fuse-fusible-link-keeps-blowing.574/

it has the wiring diagrams for the ZD21. May it will help.

 

[Dustyx2]

Since replacing the "box", will the key shut it off? I put the "low voltage relay" mod on my ZD due to too much voltage drop through the safety switches to activate the starter solenoid. If the key still won't shut it off that mod won't help that issue.

 

[lugbolt]

there are a lot of places on ZD's that don't get cleaned very often, and the wiring often corrodes up inside of the insulation.

I've run into this on 21's and 25's and 28's mostly. But then again we didn't sell many ZD18's so....

Voltage drop test will isolate where your issue is, if there's a connection or corrosion issue somewhere.

 

[Mark_BX25D]

The ignition switch tested good.

Can you give some detail on how you tested the ignition switch? The symptoms sound like that's the problem, so I'm interested in digging deeper there.

 

[Blue]

Have you checked all the fuses? Go to this post: https://www.orangetractortalks.com/forums/threads/40-amp-fuse-fusible-link-keeps-blowing.574/

it has the wiring diagrams for the ZD21. May it will help.

Yes, all the fuses are good

 

[Blue]

Can you give some detail on how you tested the ignition switch? The symptoms sound like that's the problem, so I'm interested in digging deeper there.

I tested the switch as per attached and it checked out OK

 

[Dustyx2]

I'll ask again. Since replacing the "combination box" will the switch turn the engine off? I believe you are fighting the same battle I did several years ago on my ZD. I had starting issues that I could overcome by wiggling steer levers, park brake, mower clutch handle. Always managed to get it started. Then it wouldn't shut off so since the wife occasionally uses the mower, I had to get it fixed. I went down the the checking the key switch function and nothing wrong there. That's when I found the failed "combination box". That cured the not shutting off problem but didn't help the starting issues. Checked the voltage at the starter solenoid and was only getting 10-11 volts through the safety switches. That wasn't enough to fire the start solenoid. That led to installing the low voltage start relay fix. Has been flawless since.

 

[Blue]

Since replacing the "box", will the key shut it off? I put the "low voltage relay" mod on my ZD due to too much voltage drop through the safety switches to activate the starter solenoid. If the key still won't shut it off that mod won't help that issue.

Since replacing the "box" the key still won't shut off but I did find that the stop solenoid was bad, it should be in today. But it still wouldn't start with the key either after replacing the box

 

[Blue]

I'll ask again. Since replacing the "combination box" will the switch turn the engine off? I believe you are fighting the same battle I did several years ago on my ZD. I had starting issues that I could overcome by wiggling steer levers, park brake, mower clutch handle. Always managed to get it started. Then it wouldn't shut off so since the wife occasionally uses the mower, I had to get it fixed. I went down the the checking the key switch function and nothing wrong there. That's when I found the failed "combination box". That cured the not shutting off problem but didn't help the starting issues. Checked the voltage at the starter solenoid and was only getting 10-11 volts through the safety switches. That wasn't enough to fire the start solenoid. That led to installing the low voltage start relay fix. Has been flawless since.

I didn't get to work on it today and now at 1:45 pm it is 108 degrees in my shop. I'll check the voltage at the starter solenoid in the morning and let you know what I find.

 

[Blue]

I didn't get to work on it today and now at 1:45 pm it is 108 degrees in my shop. I'll check the voltage at the starter solenoid in the morning and let you know what I find.

No voltage at all at the starter solenoid. All of the safety switches tested good but if one or more is only working intermittently it may cause my issue? I am going to jump out all of the safety switches one at a time, till all are bypassed to see if this may be the issue.

 

[Dustyx2]

You need to have the key in the "start" position when you test for voltage. If you do have no voltage at the starter solenoid with the key in the "start" position you're going to have to find where your loosing it. Probably at a safety switch.

 

[Blue]

You need to have the key in the "start" position when you test for voltage. If you do have no voltage at the starter solenoid with the key in the "start" position you're going to have to find where your loosing it. Probably at a safety switch.

My bad on earlier test for voltage at the starter solenoid, I hadn't connected the seat safety switch. After connecting the seat safety switch I am getting 10.8 volts at the starter solenoid. I installed the new shut down solenoid also. I started the engine by jumping the solenoid and was able to shut off using the key.
Looks like I need to order that low voltage relay.
You wouldn't happen to have the part number for the low voltage relay would you?

Thanks for all the help!

 

[Dustyx2]

There is a John Deere part number for a kit but you can use just a common relay. I used one I had laying from some other project. I'd just run to the part store and get one. The one I used is rated at 40 amps.
Pretty easy mod if you understand relays. You'll need a little wire and common terminals.

 

[Blue]

There is a John Deere part number for a kit but you can use just a common relay. I used one I had laying from some other project. I'd just run to the part store and get one. The one I used is rated at 40 amps.
Pretty easy mod if you understand relays. You'll need a little wire and common terminals.

Thanks Dustyx2,
This should fix my issue

 

[Dustyx2]

You can search this site or Google it for instructions if you get stumped. Think of this as a slave relay. The key switch supplies power to the slave relay and the slave supplies the voltage to the starter relay.

 

[Captain13]

I took my old one to Napa and they had a replacement in stock.

 

[Dustyx2]

I took my old one to Napa and they had a replacement in stock.

His issue isn't a bad start solenoid. It is voltage drop through the safety switches.