Troubleshoot a 7 pin snowblower

[a5t1]

A friend of mine has a '18 toolcat with an older 72" SB200 snowblower on it. When it's hooked up, auger works but chute won't rotate nor will the hydraulic cylinder operate. I began by checking for 12v at the machine 7pin, which there was. The bobcat CAN bus will send a signal to the control box on the attachment and that control box converts the signal to 12v. I then checked the 4 connectors that come out of the control box (while he was pushing the appropriate buttons in the cab) and control those attachment functions - there was 12v there. So I labeled the connections and everything seemed fine. Tested it and everything was working. He called a day later and say it stopped working again. I'm assuming a bad electrical connection and will troubleshoot in the next day or so. Has anyone else checked ohms in the attachment hardness or experienced intermittent failures from the attachment control box?

 

[seville009]

I can’t help with your specific questions, but when I had a plow on my truck, I frequented a snowplow forum alot, and there were many similar questions whereby the most common solution was that one of the male pins in a connector was missing or bent and not making contact.

Your question kind of reminded me of that, so I’m just passing it along in case it helps…..

 

[a5t1]

Appreciate it, all pins looked good - cleaned with electrical cleaner as well. I'll get some photos up the next time I go over there to help.

 

[laurencen]

you could have a solenoid going bad or the connection at it, is it always the same function on the blower not working? you could try switching the connectors on the solenoid around and see if it still fails to work and the issue moves to another function

 

[a5t1]

Thanks, it's both the rotate AND the chute height adjustment that doesn't work. But the auger engagement does work.

 

[laurencen]

auger is a single valve on and off where the others are 2 way valves, we made up a test light that fits the connector to the solenoids, that way we see a visual of the power going to the valve.

its way easier than the volt meter

 

[a5t1]

Can you post up a picture of it? I was using voltmeter to see if 12v was getting there it was, now it isn't. I think harness, wire or controller on attachment.

 

[laurencen]

its at the shop, its a connector that plugs into the harness where the solenoid goes and a 12 volt pigtail for a automotive bulb

 

[ruffdog]

I went through my service manual looking for anything on the 7-pin and have not found anything yet. Grrr.

 

[ruffdog]

The 7-pin is digital? Interesting read:
Help needed to troubleshoot Bobcat 7-pin connector functions
Skid Steer Genius FAQ Page - Everything about attachment controls.
Viewing a thread - bobcat 7 pin electrical attachment plug ?

 

[laurencen]

one thing with a voltmeter it may read the voltage bur drop when a load is attached, thats why we use the bulb, you can get a 12 volt bulb with pigtails from any auto parts shop (not LED style) I can not recall the connector, got it from Bobcat dealer but anything that will allow contact with the factory harness connection

 

[a5t1]

I'm not an expert but here is what I know about the 7 pin:
Yes, the 7 pin setup operates off of a CAN bus system (and is one of the reasons bobcat attachments are so expensive, b/c you need a controller to interpret the CAN bus signals vs something like a 14 pin connector that just fires 12v). On the machine side, you can test for 12v on the big pins at the machine connection to see if your controller on that side has 12v. Doesn't mean that controller is necessarily working but eliminates 1 possibility. You'll need an oscilloscope to read the digital signals on the smaller pins AND I'm not sure about that as I've never done it. If you look at your attachment, say a snowblower, the 7 pin on the attachment plugs into the machine and then it goes to a controller/control box. That controller is all sealed up and converts the CAN bus signals into 12v for the solenoids. Therefore after the controller can you test for 12v with the machine powered on (doesn't need to be running) and someone pressing the appropriate switch/button.

In this case it worked (I had 12v after the control box on the attachment) and then it didn't. I'll head over there tomorrow grab a few pictures and see what we can figure out. Again, I suspect either a bad connection at the 7pin, fault in the harness or possibly a dying controller on the attachment itself. But I'm not sure if a controller would work and then not.

 

[laurencen]

what I would do in this situation as above verify the 12v supply and use the cable ground, using a light verify output at the solinoids and thats where I would load the machine up and visit the dealer, they can easily use there machine to run the snowblower thro a few cycles and if they have a blower in the rental check the machine on there blower, had to do this with a Vee plow and my S590

my dealer is good helping me that way, also a rental shop could try the blower for you, that control box on the attachment can be checked with the dealer software but they will charge you for that service

 

[a5t1]

Long story short (after switching attachments on different machines, etc) turns out the attachment side 7pin had a loose connection. Thanks for all of the suggestions.