Keep blowing 20amp fuse on my scag cheetah 2 mower

[Kraner35]

Hello my name is chris, I am having a difficult time fixing my 61" scag cheetah 2 mower. It has a 37 hp EFI Briggs motor. Everytime I turn the key to the on position the amber light comes on and immediately the 20 amp fuse blows under the seat. I have already replaced the Ignition switch, the seat safety switch, the relay in the panel where the Ignition switch is. The starter and the battery. Please give me some guidance. I also checked the ohm resistance on the clutch and my reading was 3.2. Thanks for any feedback and help....

 

[shurguywutt]

Sounds like there is a short somewhere... Get out the wiring diagram and trace the circuit to see where you need to check.

 

[Lubener]

There is a short to ground. Check for any pinched wires. Using an ohm meter, you can start disconnecting items till the short to ground disapears. You should be able to narrow it down. A switch likely will not cause a fuse to blow. A switch is either open or creates a short to function but not to ground. Try disconnecting the clutch and see if the fuse blows. The clutch coil should be fairly low resistance but 3.2 ohms across the power source would blow a fuse in my opinion.

 

[Gyro Gearloose]

If a visual check for abraded or pinched wires doesn't turn up anything, you can go the intellectual route by downloading the owners manual with the wiring diagram off Scag.com. Manuals are available by model and serial numbers under the Resources tab. The wiring diagrams will be toward the back of the manual around page 85 +/- .

Looks like every model mower feeds power to all the interlocks and accessories from a common terminal block or connector. If you can locate that common connector, break it apart and see if that stops the fuse from blowing. If good, then check each wire in the connector for ground . Be aware that anything that is normally "on" when the key is on - like the engine computer or instrument cluster - will show up as grounded or low resistance when you check that particular wire. Since they use the same color wire for every circuit this process could be a bit of a challenge.

The clutch should not be engaged and drawing power when you turn on the key so I don't think that is a factor.

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[Kraner35]

I appreciate all the feedback I will look into the suggestions today and get back to you with what I found. Thanks a bunch !
- chris -

 

[Kraner35]

There is a short to ground. Check for any pinched wires. Using an ohm meter, you can start disconnecting items till the short to ground disapears. You should be able to narrow it down. A switch likely will not cause a fuse to blow. A switch is either open or creates a short to function but not to ground. Try disconnecting the clutch and see if the fuse blows. The clutch coil should be fairly low resistance but 3.2 ohms across the power source would blow a fuse in my opinion.

Do you think that 3.2 is too high then...? I unplugged the connector for the clutch and it still blew the fuse.

 

[SHOZ]

You need a volt/ohm meter and learn how to use it for tracing grounds or shorts. Fuses are meant to protect the wire not the device usually. So going bigger is not usually the answer.

The clutch should go though a switch that you activate before any electricity is allowed to go there.

So if it blows with the key off and switch off upon connecting there is a dead short in the switch for one. Maybe it's melted?

 

[oldgrayman]

It blows in the ON position , before you turn it to START ?

 

[Kraner35]

It blows in the ON position , before you turn it to START ?

Yes

 

[BigCahuna]

I would look at the wire from the switch, that goes to the starter solenoid.It might have somehow gotten pinched, or worn thru to the point it's making contact with metal.,,

 

[oldgrayman]

There are not a lot of things that get energized in the ON position . You really need a schematic .