Help with Cat 299D skid steer

[kyle sutton]

Looking for some help with our 299D skid steer. The quick coupler to change bucket to forks isnt working from the switch inside the cab. I can use my power probe and apply a ground and 12 volts directly at the back of the coupler motor and it will work fine. I only have 3.6 volts and the back of the switch coming from the ECM. I have replaced 3 relays in the engine compartment on the unit still voltage is 3.6 the last 8 of the Pin are JST01217 thank you for any help

 

[Nige]

If an Electrical Schematic would help you with your diagnostics then you'll find one below.

 

[Nige]

Sorry, forgot to ask. Do you have any Active Diagnostic Codes..?

 

[kyle sutton]

Thank you for the schematic and no sir there were no codes active or stored

 

[heymccall]

J5 on diagram shows fuse not in panel.

 

[Nige]

373-1592 on the Electrical Schematic is actually listed in the Parts Manual as "Circuit Breaker - Automatic". It appears to be part of the 356-6117 wiring harness for the QC. I can't find a picture of it anywhere.

 

[heymccall]

Schematic Nige posted shows breaker @ #48

 

[kyle sutton]

thank you very much for the diagrams. This thing is killing me i have 12 volts at the two relays in the back of the machine but still 3 volts to the switch

 

[heymccall]

The switch is most likely not full 12v anyways. It just commands the ecm to trigger the relays.

 

[kyle sutton]

Makes some sense but at my relays in the back when i probe it to check power it goes from 12 down to 3.6 on the wires that run to the QC motor itself. Im confused as to what would cause the voltage drop both relays are brand new

 

[Nige]

The only thing I can suggest (if it’s possible - I haven’t studied the schematic in detail) is to disconnect everything related to the QC as far back as you can towards the relays. The start working forward one connection at a time and test. If your 12v suddenly becomes 3.6 after making a connection then forward of that connection is where the problem lies, if that makes sense.

 

[kyle sutton]

that does make sense thank you

 

[Nige]

It may also pay you to identify all the harness connectors that the voltage passes through between the relays and the QC. Open every one of them and clean with contact cleaner.

We have lots of trouble with condensation in my current location (an average of over 100” of rain per year) and we have found that Senson Electroguard grease is the best thing for keeping moisture out of electrical connectors on all our machinery. If it works here it should work anywhere.

 

[Dino Grigorescu]

Hello.
Did you ever figure out what the problem was?
Im having the same issue with my skid.

I had this problem before. i removed the motor then opened and cleaned it but now the problem is back.
The switch and relays check out. i cant find the breaker to check that out.
Any advice would be great.
Thanks

 

[Nige]

Follow the same diagnostic steps as suggested above would be my first thought.
The Electrical Schematic posted above is good for machines with S/N prefixes B5W, ETL, BE7, HP7, GTC, & JST. If you machine is not in that list then post a S/N and I'll see what I can find for an applicable schematic.

 

[Hall0226]

I know this is an old thread but did anyone get this figured out? I have a 277d with the same setup and 3ish volts at the relays and switch.

 

[Nige]

It’s somewhat irritating when posters don’t come back and tell the forum what the fix was.

All I can suggest is similar to what’s posted above. You’re going to need an electrical schematic and to identify the correct one will require your machine Serial Number.

 

[Hall0226]

Yes. I would love to know what everyone else found.
The 3v at the switch and at the relay is strange. I send you a private message with my serial number.

 

[Nige]

Check your messages.
Also I'd ask the same question as above. Do you have any Active Diagnostic Codes.?

 

[Hall0226]

Thought I would update:

found 2 problems.

First the machine only outputs 3.6v when engine is off but key on. This is normal. I was only getting 3.2v. I found my main fuse holder beside the battery was rotten. Actually fell apart.

Second problem after we got the relay to close was a broken wire by the front causing an intermittent problem.
Hope this helps someone else