Hi , First post ! I have a 2005 Cat 262b that has started blowing the 10amp interlock fuse. Tonight I went slow and It happened after I started it and move the Right joystick ( loader control) Any one have this happen and can save me some time ?
I replaced the fuse again and turn the parking brake off and it popped fuse. I lifted cab and dont see any broken wires or anything. If anyone has any input I would greatly appreciate it
Would an electrical schematic be of any use to you.? With that you could investigate where the short is downstream of the fuse that is blowing. If so it would need a Serial Number (probably PDTxxxxx but need to confirm that) to get the correct one.
I have the schematic - pdt00748 , I did look at the wires and dont see any broken or even chaffed against anything. Im going replace the parking brake solenoid ( 100 bucks) Cant get part til monday. Hoping the ECM is not the problem !!! Do you think a bad parking brake solenoid could be causing this problem ? Not much anywhere online about this issue
What all is that fuse protecting? Whatever else is on that circuit you can unplug until you stop blowing fuses. Or my preferred method is until my meter stops showing a short to ground. Chances are being ecm controlled ground is supplied from the ecm. In that case you will need to put your meter lead onto that ground.
I agree with Paul. Disconnect everything downstream of the fuse for a kickoff and start reconnecting from the fuse going in the direction of whatever it supplies. When you connect something and the fuse pops, voila......
Using a digital multimeter, you can verify whether the solenoid coil is shorted or not. I dont recall the actual resistance value, but, it, most certainly, shouldn't be less than 5 ohms. The other tool less way...unplug solenoid, replace fuse, and operate the park brake switch. If the fuse no longer fails, odds are the coil is bad.
10 ± 0.5 ohms according to the table on Page 8 of the schematic. EDIT: I've had a bit of a skim through the schematic and I can see no connection between the park brake solenoid and the Interlock ECM fuse. As far as I can see that fuse (#F16) feeds two locations via wire #128 Pink. It's the Interlock ECM power supply and is a live feed when the keyswitch is in the ON position to the Aux Bleedoff Switch on the LH panel.
On my machine its F19 fuse F16 is the aux hydraulic ecm fuse at least thats the way im reading it
This is from the schematic that I have
its for sure the f19 the is blowing
Sorry, my bad. I thought it was the AUX that was blowing. When I get chance I’ll have another look. EDIT: Nothing else on that fuse other than the interlock ECM. As HMC suggested, try measuring the coil resistance of the parking brake solenoid compared to spec. If that shows nothing, I suggest to get the floor up and take a look underneath at the condition of the ECM connections and see what they look like. It won't be the first SSL to be full of mud under the floor plate.
I did trace the power wire back to main power relay A -
What wire # & colour were you tracing.? Power wire for Interlock ECM is 126-AB4 Pink. I don't see it going anywhere else.
I may have a different schematic - I have 126 -a84 pk 18 on other side of fuse its 112 a73 pu 12
OK ! so I did some redneck diagnostics - Went and unplugged the parking brake solenoid and fired machine up - hit parking brake switch - fuse held - Plugged the machine back in with solenoid plugged in and as soon as I hit the parking brake it blew fuse. New solenoid will be here in morning from CAT - Stay tuned !!
I just got back from a walk and while i was out i had a bit of time to think about it. What you did was exactly what I came up with. I just hope it's the solenoid and not an internal problem within the valve itself.
A stuck "valve" would have no influence on the coil's performance, and, most certainly, a stuck "valve" would not fail a fuse. I came up with 195-9700 @ $100, and, the coil is integral to the cartridge.
Just put new Brake solenoid in and fuse didnt blow when I hit the parking brake ! Tried it several times - seems to be fixed. Thanks for everyones input See ya on the next break down ! A little Cat humor