We have an 03 or 04 257 and it starts just fine but the parking light indicator and I think seatbelt light are flashing (park brake relay is also clicking, I did replace the relay with new, as well as the one next to it. I think that was the seatbelt relay). It won't move or do anything other than motor run. I was reading it could be the brake solenoid or a wiring issue. Wondering if anyone can point me in the right direction where the solenoid would be and maybe where the trouble spots in the wiring might be? Or any other advice. Thanks!
If a relay is clicking and the light flashing consistently you may have a shorted solenoid tripping the breaker(s). I would order up a tech manual to ID then diagnose the solenoids and inspect the wiring to those really close as these machines beat the hell out of harness.
I was on the phone with Cat trying to get some guidance... I have the schematic now via email (if I can make sense of it) maybe I can get somewhere tracing wiring. After I got of the phone I decided to start it and see if the park brake would disengage. It did. Trailered it to the job, pulled a tree down, lifted some big limbs into the trailer. Over an hours time, we started and stopped the skid about 4 times. The last time we parked it and came back a half hour later and got the clicking again and brake wouldn't disengage. We did what we could on the job without it and before we went home spent an hour getting the 2 bolt off that hold the cab down. Tomorrow morning I plan to check grounds, the ohms on the solenoid and look at wiring harnesses. I'm tempted to figure out how to get 12v and a toggle switch so we can use it!
Caution with that as you do not want to back feed into the ECM and cook it.