CT122 electrical gremlin

[jonnyc1999]

Hey guys, I'm hoping you can help me before I have to pay someone to come out and look at my tractor. The other day, I started my CT122 up and piddled around with it for roughly 30 minutes. I shut it down to do something, and 10 minutes later came back to the tractor to start it. Nothing happenned! Well, to be more precise, nothing that I WANTED to happen. The dashboard lights were barely visible but flickered and made a crackling sound, and turning the key didn't engage the starter at all. I assumed it was a faulty ignition switch so replaced it, which didn't help anything. I tested the battery at 12.1 volts.

I'm not well versed in anything electrical, so any help you guys could give would be GREATLY appreciated! I would hate to call a technician out for something stupid. My dad thinks it sounds like some sort of relay issue, but I don't know what a relay looks like or how to test one! Thanks in advance for your help.

[MossflowerWoods]

Check for loose/corrodded terminal on batttery.

[jonnyc1999]

I looked at the battery terminals, and the ground on the negative side looked a little rusty.... however, I ran a jumper cable from the ground to the engine block and didn't fix anything. It was pouring rain, then snow, when I was last looking at it, so I'm going to clean the ground tonight and retry.

[SSdoxie]

Check both ends of both battery cable connections, especially the ground to frame connection.

[k0ua]

The majority of these type of problems are due to defective (corroded on the inside) positive and negative cables. They look fine on the outside but are full of the greenish white powder of corrosion on the inside of the cable and hence are a high resistance connection. Another common failure mode is a defective battery with a high resistance connection inside. It may show 12 volts but when you try to pull much current from it, it exhibits a severe voltage drop. You can measure that by having 2 persons to do this check. One person operates the tractor and tries to start it, and the other person measures the voltage directly on top of the battery posts, NOT on the connector clamps, but directly on top of the battery posts. If the voltage drops much below 12 when the instrumentation and lights come on or below 10.5 when fully cranking, then you have a battery problem. If the voltage stays up, but the tractor does not crank, and the instrumentation/lights are erratic, then the problem is further down the line. Simply move the voltmeter leads further down the line to find the voltage drop.

James K0UA

[MossflowerWoods]

Jon,

K0ua and SSDoxie are spot on. I was gonna say check other end of ground cable, but I know James is spot on about corroded cables also.

Hope BobKitty runs tonight!

I'm firing mine up later today for bonfire prep...
1st time in Months...

David

[jonnyc1999]

Ok thanks guys, I'm at work right now, but this afternoon I'll definitely check it out!

I'm not looking forward to paying a technician to drive an hour each way to diagnose this problem, so I'm gonna do as much footwork as I can beforehand!

[SSdoxie]

12.1v is low voltage for battery with no load on it. 12.5 = about 80% fully chraged battery. When you turn the key for the first 15 - 20 seconds the glow pulgs are energized, which pulls significant amps so a with low battery or internal failure in battery it may not have enough reserve capacity to power up the dash.
Do all the checks above, especially the vlotage drop test with key on that James described. Recharge the battery and retest the voltage drop under load again. If it drops down in that 10.5v range again have your battery load tested.

[jonnyc1999]

I was thinking 12.1 was a little low too, but what threw me off was that I had been using the tractor for ~30 mins prior to shutting it off for a few minutes. I guess when I get it started I need to figure out if the alternator is actually charging!

[jonnyc1999]

well, I ruled out the battery tonight. After charging it for a bit, it read 12.5 volts. I couldn't sit on the tractor and get multimeter readings at the same time but by turning the key to run, the battery still showed over 12 volts. With the key on run, the dash flickers and hisses, but won't do anything productive. The starter will not engage.
I ran the battery down to autozone and the battery tested slightly discharged but good, at ~450cca. When I got home I sprayed the positive terminal down with battery terminal cleaner to get rid of the small amount of corrosion and called it a night. I still need to test the voltage from the other side of the positive terminal to determine if the positive cable is the issue.
At this point, I'm still considering that the issue is a relay. I'm guessing these are all under the dash? Is there a way to test if a relay has gone bad? Thanks again guys for your help, I'm enjoying learning about electrical stuff even though this is pissing me off!