MonteCarlo31

Help my 06 silverado w/ 5.3 and 4L60E 4x4 is on the fritz. I keep getting a check brake system and my 40 amp under hood fuse for the ignition keep blowing. It started last night while out to dinner but ran fine all day with a 60 amp fuse in place, switched it to a 40 amp at lunch and started about 10 times before blowing, now it constantly blows fuses. I've got thru 3 fuses. Any ideas? Truck will not start now, I can get it started with a 60 amp fuse but know that isn't safe. Any help would be great. You can hear the fuel pump cycle on and then boom the fuse is gone before I can start it. Truck runs fine drives fine etc, not sure what the issue is.

Thanks in advance.

mcfarlnd

iTrader: (15)

your gonna have to start chasing wires man, you definitely have a short somewhere. start at the fuse block and follow the wires till they terminate. look closely but, more than likely if it is a wire blowing that bigger fuse, it'll be burnt and noticeable.

MonteCarlo31

I've done about all I can as of right now, all relays are working ok, now the headlights are looking dim like theres a draw even with the blown fuse out, Ignition fuse B is not blowing, just ignition A is blowing. It blows only in the run position not the accessory position. Anyone have the wiring diagram for this truck?

Thanks

KySilverado

iTrader: (7)

Not an 06, an 05 schematic. Bet they are same.

My guess is the starter.

built408

iTrader: (10)

Check the draw on the starter when you crank it... Sounds like a starter to me too.

MonteCarlo31

Thanks for the tips, I can't check the draw on the starter because as soon as I turn the switch to the run position it blows the fuse. I am also not receving the Driver 1 or 2 message in the DIC like normal. I pulled the following codes too. P2761, P0785, P040 and Nd041. Not sure if this means anything. After the fuse blows all accessories work fine in the truck. Not sure where to start, open ground? Bad key switch?

Torque_Wrench

iTrader: (13)

Bro, I'd get under the hood and loosen up the UBEC (fuse block) and turn it over, and examine the wiring going into the fuse block. Those things have a tendency to fail. Make sure you don't have a shorted wire going into the fuse block and be sure to test the terminal where your ingition fuse plugs into. If you have an amp meter, plug your two leads into the fuse terminal for the ignition fuse and check the amperage going to that terminal. If it's way over the 40 amp rating then you are drawing an overcurrent. Just remember, you'll have a bit more amperage because the fuses may say 40amp but they rate just higher than that.

MonteCarlo31

Ok, here's what we did tonight, removed the starter relay on the engine fuse block, then cycled the key to the run position, when we did this the fuse did NOT blow. We then removed the starter, only a 25 min job if that, took it to the auto parts store, they tested it and said it was good but the guy didn't look too sharp, it drew about 100 to 125 amps when he triggered it on the starter. This was the draw, I assume on the main HD wire running from the power source to the starter. When the starter was removed we cycled the key forward with the starter relay in place it did not trip the fuse. So where should I go from here? It did drain the battery all this starting so when I hooked up the powerstroke to the truck via jumper cable the ABS/Brake system failure light went out. Should I slap a starter in it even though they say it's good? should I check the wiring harness? I don't see any frayed wires or damaged wires via visual inspection. I'm at a loss here.

KySilverado

iTrader: (7)

There is probably a short inside the starter. MY guess only. I would slap in a starter.

MonteCarlo31

I'll get a new one Thursday and install it that night if that's not it i've been told it's the ignition switch which will throw the 4 codes I'm getting. I'm hoping it's not that as that is some serious $$$ with the VATS system.