Emergency stop circuit

[Blackeyes02]

2004 BF150, Engine starts and runs with or without the "Dead Man" clip in place. While trouble shooting found a broken wire (blk /w red trace) on the ignition switch, part of the grounding system and indicator light. Could not repair so replaced the ignition switch, did not solve the problem. Per the wiring diagram the bulk/red wire goes to the ECM (ports ems1 &ems2. I jumpered a ground wire at the dead man switch and the system operated as designed. I suspect the problem to be in the ECM but not sure.
Checked all connections on the wire, had continuity to ground all the way, seems like the bulk/red wire is not getting a ground signal from ECM. Am I on the right track. Would the ground wire jumper be a suitable fix?
Any help appreciated
Greg

 

[chawk_man]

Don't know much about the 150, but their systems are a lot like the BF 225.

First thing I would do is check the 4-prong connector for corrosion or bad contact. See attached diagram - "Stop". It's for a BF 225 dual engine, but I think same for BF150.

Also, check the connectors on the PGM FI relay.

 

[jgmo]

Agree with chawk_man. While I DO think your "extra ground" to the emergency switch is a reasonable work around and you could just live with that, if you want to fix it right you will need to find the OTHER open in the blk/red wire. And, as chawk_man says, there's a high probability it's in the plug contacts of one of the multi wire connectors.

I have a crappy PDF wiring diagram for a 130 and it has a green connector and a blue connector. The blk/red wire goes through both of them. The 150 might be slightly different but most of the models are similar to each other for wiring. Sometimes just unplugging and using some contact cleaner on those pins and sockets then plugging back in will restore contact.

That blk/rd wire is a SINGLE wire but near the ecm, they "T'd" it so it provides 2 wires to go to ems1 and ems2. It's possible that it could have come apart at that T. Maybe corrosion. Look for a taped spot or shrink wrap where the blk/rd wire splits near the ecm.

It's NOT the ecm causing this. You already proved that with your "add on" ground making it work.

Good luck.