So, this is going to be more of a roadmap of what ive encountered for whoever may have a similar issue. Serial: MDH04684 2007? Cat 277B multi terrain loader with 3500 or so hours Feel free to chime in with your ideas. Symptoms: Start machine- turn off parking brake with arm bar down; everything works except the parking brake is stuck on (even though the light is turned off) and the brake pads are screeching..... clearly the brake is engaged I figured, "ha probably the solenoid is burned out". Replaced the coil... nope, still stuck. So after conversing with the dealer parts guy, he pulled up the hydraulic control group for the parking brake (3 hoses and 2 wires going to 1 connector) and when he tried to order it, it comes up as obsolete and it suggests this part -> tried to order, and its been superseded by this new control block, pulled that thing up and its $380... ok, whatever, order it. Comes in and it has 4 ports, 2 solenoids and 4 wires going to a single plug... clearly NOT what I need. It looks like an accessory block with ports T (tank) P (pressure) C1 and C2 for circuits 1 and 2 going to a hyd motor or ram... and its controlled with PWM.... handy to know in case I wanna add an auxiliary. Back on track! I returned the part and decided im going to just take the control group I have now apart and drop a ball bearing into the spool to hold it open; itll have to get me down the road til I can sort this all out. On the drive home I was thinking.... I checked the voltage at the plug for the solenoid and it was 13.8v.... unplugged, NOT under load, so perhaps there is some corrosion and cannot deliver the necessary current for the solenoid to do its thing.. So I loaded the machine up out of the road (where its been stuck) and hauled to my favorite shade tree, hooked up a set of LONG test leads (clip cords) directly to the parking brake solenoid coil and touched it to the battery with no background noise.... and it clicks! **, what do you bet this thing works fine? Sure enough, left the cords attached, started the machine, disengaged the parking brake and it moves fine now. SO in closing.... I have a wiring issue, the schematic shows the wire goes straight from the ECM under terminal 13 (A958) and goes to a whole host of connectors and splices. Ive also had a weird intermittent issue with the auxiliary hydraulics randomly stop working, but the main lift arm and tracks work... I think all of this is caused by the ECM interlock computer part number 154-4233 ( operator_interlock_control ) terminal 24 wire p988 goes to the auxiliary control coils M-C3 and M-C4 as a PWM square wave... I relocated my ECM out of the foot well back when I first got it to prevent it from just sitting in mud and grease the rest of its life. Its located on top of the fuel tank now. The only issue I see is I never reconnected the chassis ground since its just sitting there zip tied to the tank. Maybe this can cause an issue? But its seemed to work just fine for SOOO long. I appreciate any input. Sorry, I didnt mean to write out a whole phone book worth of notes, but hopefully it helps someone.
How did you fix this?? I'm having ecm issues and thinking of just hot wiring with a switch, 12 volts to all my solenoids and taking the ecm out of my issues. They want 3 grand for the ecm, and would be my second one!