?No Crank, no juice to ignition: any Suggestions? / advice?

[monkfarm]

More Problems with my 2002 Scag Cougar with the Kaw engine. I didn't have any problems for years, so now here they are. I had the mower start to cut out on me lately while mowing, and I just shut the key off and started it again, and it would run for another half hour.
Now, It will not start, and I can't hear the fuel pump cycle, even though the battery is at 12.94 volts, (stays right around there, so I know the battery is good.) I can't find any juice coming to the ignition switch when I put the multimeter on it. i have a new seat switch, and examined the wiring, bypassed the pto deck engagement switch shutoff. I think it might be the relay, so I ordered another relay, but I have a similar relay from a truck that I plugged in, and no go, so I'm not too sure that that is it. It could be I need the correct relay, so that is coming. I looked over the wiring, and I have a new ignition switch. Any other suggestions would be appreciated. I'm just a back yard mechanic, fumbling around in the dark, and try not to be a know it all. I am stumped. I also ordered the electronic module for this $99.00 This machine is 13 years old now, but garaged with 692 hours. The battery connections are nice and clean, and tight.

 

[bertsmobile1]

Start by going to Scag and downloading the operators manual which from memory has a wiring diagram.
You must have power to the ignition switch.
Power goes from the battery to the switch , usually via a fuse , then to the various safetys and finally down to the starter solenoid.
The power feed to the ignition switch is usually the red or some times a red & white wire.
Start there and see where you are at.
DO not go ordering more parts till we have had a chance to go through it with you,
If it is nothing more than a 25c fuse tou will not be a happy chappie.

 

[reynoldston]

I sure have to agree with bertsmobile1 to quit buying parts you don't need to buy unless money just means nothing to you? I don't know your electrical skills but start with a wiring diagram. This will be your road map to the repair. I do this type of work all the time and a wiring diagram is the very first thing I start with. Just too many brands, models, and years mowers that no two are alike to know this information. You might just save more money by taking this to a skilled person then to keep buying useless parts not needed.

 

[monkfarm]

Thank you so much for your Replies!! I appreciate your responses! I have been looking at the wiring diagrams all along, and have checked all the fuses. . . (I think there is only 3 fuses, did I check all of them? I will look again!) I checked the fuses visually, and with my multimeter. The repair persons are expensive around here, and also not reliable, plus, they take weeks to look at the machines, and often haven't fixed them, when they are returned. $130.00 worth of parts is nothing compared to my neighbor's repair bills for his two Scags who takes them to a mechanic 40 miles away. I live out in the sticks. This is an '02 machine, and the two parts I ordered (relay and electronic module) are known for failure (what I read in here.) I appreciate any other suggestions, and will trace the path you two suggested. (Not today, but tomorrow) Thank you!

 

[bertsmobile1]

Print out the wiring diagram as large as you can.
Get out some coloured pencils and trace out the paths that control the starter and only the starter.
So if the starter does not crank, the problem will be on these wires and nowhere else.
If you like work out which wires will be live and mark then with a nice big red X so when you get back unde the mower you just need to check the X's for voltage

On another copy trace out the wires that control the ignition and only the ignition
If youhave no spark then the problem will be in these wires and no where else

Believe me it makes the whole electrical trouble shooting a whole lot easier.

I use a can of spray contact cleaner ( from an electrical geek shop ) and wet down the terminal plugs then make & break the contact several times.
Another squirt up the guts of most of the switches usually works wonders as well.
Finish off with a squirt of Innox ( WD 40 on steroids )

The hard ones are the wires that break just at the crimp so they look sound but make & break contact at will.

You can bypass the relays using a short jumper with a male spade on each end the way the circuit is complete and you can then test the trigger wires for both power and earth.
Oft a bad earth contact in the loom wire will be the culprit as the relay must have both a + & a - at the plug or it can not trip.

 

[reynoldston]

Like I said we don't know each others skills, but I have been doing this type of work for many years. I can only give you some words of advice. Take your time and only work on one circuit at a time. Use your wiring diagram as a road map and when you come to a switch ( all a relay is, is a electric switch) stay with the circuit you are working on. Do not repeat work which is very easy to do. You will come across and see the problem when you get there.

 

[monkfarm]

Like I said we don't know each others skills, but I have been doing this type of work for many years. I can only give you some words of advice. Take your time and only work on one circuit at a time. Use your wiring diagram as a road map and when you come to a switch ( all a relay is, is a electric switch) stay with the circuit you are working on. Do not repeat work which is very easy to do. You will come across and see the problem when you get there.

I appreciate it, Reynoldston! Good advice! I will go back to that, and go over the circuits, one at a time. You're right, I tend to go over everything expecting the problem to jump out, and it will, with focus, and determination. Thanks, I needed a reminder.

 

[monkfarm]

Print out the wiring diagram as large as you can.
Get out some coloured pencils and trace out the paths that control the starter and only the starter.
So if the starter does not crank, the problem will be on these wires and nowhere else.
If you like work out which wires will be live and mark then with a nice big red X so when you get back unde the mower you just need to check the X's for voltage

On another copy trace out the wires that control the ignition and only the ignition
If youhave no spark then the problem will be in these wires and no where else

Believe me it makes the whole electrical trouble shooting a whole lot easier.

I use a can of spray contact cleaner ( from an electrical geek shop ) and wet down the terminal plugs then make & break the contact several times.
Another squirt up the guts of most of the switches usually works wonders as well.
Finish off with a squirt of Innox ( WD 40 on steroids )

The hard ones are the wires that break just at the crimp so they look sound but make & break contact at will.

You can bypass the relays using a short jumper with a male spade on each end the way the circuit is complete and you can then test the trigger wires for both power and earth.
Oft a bad earth contact in the loom wire will be the culprit as the relay must have both a + & a - at the plug or it can not trip.

Thank you, Bertsmobile, I just noticed your reply here also. Really good suggestions, and I will try the jumpers when I work on this first thing tomorrow. And I will go over the grounds as you suggested, that could be the problem right there. Wish you all Well, Dean

 

[bertsmobile1]

No need for the extra thank yous, while they are always appreciated what is important is you get your unit going and let us know what exactly was wrong.
It helps te people offering the advice and those who lurk looking for answers to their problems.

 

[monkfarm]

Well, it's going!! Yeah! But, I'm not sure what the problem was. I didn't keep trying it every time I worked on a connection, or checked this or that, so I wasn't scientific enough about it. I guess when I put it together, I'll have to double check everything I did, to make double sure the problem doesn't reappear. The problem could have disappeared when I cleaned the ground (or earth as you Aussies say), or cleaned the fuse holders with electronic contact spray, or cleaned t he contacts for the switches or ?? Thanks again for your suggestions, it made my determination to fix the problem stronger.