1999-3186 Safety Interlock Failure

[jb1961]

Unit starts as usual. PTO off. However, when the brake lever is released, the engine immediately cuts out. In other words, the brake lever sensor is tripping at the wrong time. You should know that the seat sensor is completely disconnected (intentionally) and up to this point, its absence did not effect the operation of the tractor. First, where can I find the brake safety interlock? Second, could one of the other interlock sensors have something to do with tripping the brake sensor? Thanks. JB

[tractordude]

You have a bad relay, look for a little black box

[Sam Mac]

Get a copy of the wiring diagram then off to the local auto parts store for some electrical connectors after you figure out how to by pass the Gov mandated safety stuff.

[jb1961]

Surgery scheduled for later this weekend. Will post prognosis and probably pre-order a new relay. Seeing on how my 83 year-old father operates this beast regularly, I would rather keep most of the safety features active...thanks for the feedback.

[jb1961]

New relay installed after limping through late summer. All systems worked intermittently for a while...now nothing. So we are back to square one.

Unit starts but as soon as you let off parking brake, the engine kills. I remind you that the seat kill switch is disconnected. I plan to crawl under there today looking for a brake lever sensor of some type. Is there a sensor at the transmission? I cannot see one through the deck after removing seat. Help.

[jsoluna]

Originally Posted by jb1961

Unit starts as usual. PTO off. However, when the brake lever is released, the engine immediately cuts out. In other words, the brake lever sensor is tripping at the wrong time. You should know that the seat sensor is completely disconnected (intentionally) and up to this point, its absence did not effect the operation of the tractor. First, where can I find the brake safety interlock? Second, could one of the other interlock sensors have something to do with tripping the brake sensor? Thanks. JB

In my experience, disconnecting the seat switch will kill the engine on the safety circuit of the 3000 Series tractors, meaning that the switch completes the circuit when actuated, the tractor will not run unless the brake switch is also activated.

Here's a basic wiring diagram:




Access to the brake switch: rather simple. Just look up under the passenger side frame rail and you will see it there by the rockshaft for the brake pedal.

[ryanpei]

Same problem as above:

Engine cuts out when brake released.

Disconnected and jumpered seat safety switch: No effect.
I'm wondering if I have a short in the seat safety wire?

Anyone else have experience with this?

JB1961, did you ever have any luck?

Thanks,

Ryan

[FrankF3]

The schematic for this tractor has more twists and loops than what I've seen on most, but working backwards, The brake switch has 2 N/O switches and when depressed closes the start circuit to the start solenoid while the other one, is connected to + 12V of the alternator. I see a green wire connects to the engine. I assume you need to supply power to this lead to keep the engine running since it is fused in the fusebox and seems to be connected to the voltage sensor in the fuse box. I don't have any answers just observations. Have you tried to re-seat the voltage monitor and other connectors?


3186.jpg

[Alvy]

JB and Ryan, wow this is an old thread, I know you have stated that seat switch unplugged hasn't effected operation up to this point. However, as Jsoluna stated, most later model units have an internal jumper inside the seat switch plug itself that is spring loaded and closes the circuit to prevent owners from unplugging it and bypassing. You may want to see if that seat switch path is grounded now as maybe movement has made the internal jumper finally activate inside there if there is one. Just a thought.