1440 wiring problem
 

I have a 1440 that is blowing fuses. I have tried the following

-Solenoid seems fine. I can bypass the switch circuit by going straight from the battery to the solenoid key terminal and it will turn the engine
-Checked ignition switch- no shorts
-Checked PTO switch seems to be good
-Disconnected dash wiring harness and head lights-still blows fuse
-Checked seat switches- working fine
-Noticed that there is continuity between the wires for the head lights and the yellow wires going to the magneto at the block for the key switch (is that correct, didn't seem right to me) Pulled those wires out of the block so not in contact with the switch but fuse still blows when turned to run.
-Disconnected wires from Voltage sensor- still blows
-Have NOT checked the brake switch since it is buried.

So short of dismantling everything to get to all the wires to look for shorts anybody got any good ideas?

Key switch is grounded to the frame through the case of the key switch and uses a "ground" terminal on it to kill the magneto in the off position. You need to check for continuity between the "R" terminal and ground in the run position with the key switch unplugged. It's possible that the actually key switch is shorted. You say that you checked it for "shorts" but how did you check it? You can isolate the key switch from the frame of you don't have a meter. You have very low resistance in the run circuit, you're getting there.

I'm assuming from the print that you have to go past the Run position to run with lights so if it's blowing it in run then the actual head lights/tail lights are out of the equation.

Did you isolate the fuel solenoid and alternator yet as well?

Do you have a DVM or a VOM meter...???

:bigthink:

I do have meter and not afraid to use it.

When I tested the key switch I had it off the tractor and on the bench. I tested for shorts between pins and to make sure contact was being made between appropriate pins in the different key positions. My switch has the light position as the first position so you have to turn back from run to turn on lights. The fuse blows at that position before you get to "run"

I have not isolated the fuel solenoid or alternator. Not sure which is the fuel solenoid.

Here is the Matrix for the 725-3163 Ignition Switch

Good info Roland and thanks for clarifying mister Webster. I don't have a 1440 to reference but that's what I was wondering about, key position when fuse blows.

To answer your question, the fuel shut off solenoid is located on the bottom of the carb bowl. Also, you said you disconnected the lights but did you disconnect the tail lights as well?

Did you run a test from the positions listed from them to the case of the key switch to check for a shorter key switch?

If that's ok, You're going to have to test continuity on the key positions listed above again with the harness unplugged from the key switch. There's got to be a short in one of the items listed in the print or the actual wiring going to them.

If it blows the fuse as soon as you turn the key my guess is you may have a shorted wire to the lights. I would unhook the wire to the lights at the key switch.

The lights wire is blue.

At one point I did have the blue wires to the lights and the yellow wires to magneto disconnected from the switch (as well as the dash harness and pto switch diconnected at the same time). Still the fuse blew when I turned to run+lights. So that must mean there is something in the switch that I didn't catch the other times I tested it. I have not run any of the tests with the switch mounted to the dash, either on the bench or with wires hooked to it hanging in free air.

I know the wiring diagram shows tail lights but I believe I only have reflectors back there. There are 2 blue wires coming from the switch but I believe they are home runs to each head light.

I will try some more test but it will be a couple days till I can get back to it. That pesky work thing

The 1440 (143-633-100) rolled out of the Factory with tail lights.

My 1863 is similar to the 1440. I purchased the 1863 new. The wires going to the headlights pass under the firewall at the frame on the left side. The firewall is sheet metal with a sharp edge. Perhaps look there for wire damage.