Hey guys, I'm having one hell of a time diagnosing a problem with the backhoe I'm working on. The machine drives just fine, and the front loader works. If i go to use the backhoe, I do not have hydraulic power to the out riggers or the boom. I've replaced the hydraulic lockout switch and the relay and still nothing. Doing just a visual inspection, I found what could be damaged solenoid wires underneath frame, right in front of the rear driveshaft on the right side (Pic attached). I can not find a part number anywhere on CAT's website. I also researched more and found a thread on here saying it could be the GP-Control (Inlet) solenoid or the GP-Control (Boom, Stick, Pattern Switch) Solenoid. Do any of these things that i have listed sound to be the issue? I'm currently deployed overseas and due to the leave time on parts, I really only have time to order replacement parts one time for them to come in while I am here. Thank you all
I believe you will find that the problem is the implement lockout solenoid. Mine failed and replacements can be found online indicating its not a rare failure. When you remove the rearmost floor plate you can just see the edge of it on the right rear side of the valve group. It's retained with a socket head cap screw, 6 mm socket size if I remember, and a fork clamp. After removing one bolt and loosening the two others in slots allows some movement of the valve group to the left and you can access the bolt but it's a blind operation. The solenoid may appear to be stuck but it's just the o-rings. Not sure what CAT's reasoning is for the lock out function but having designed solenoids this one is "sketchy".
Should also note you can measure the solenoid resistance at the relay pin. Should be approximately 10 ohms. Mine went to 16 ohms when the coil connection exhibited increased resistance and then failed open circuit. I think the relay pin is 87a to the solenoid and the diagonal pin is B+ when the key is on. The solenoid feed pin was on the lower right looking at the relay if memory serves.