Got back from a 200 mile camping trip pulling my 5er last night. Unhooked the RV from the truck, got set up. Get in my truck this morning and it won't crank. Checked the voltage at the remote battery terminal, got 12.46V. Connected battery charger @ 50amp engine start, still no crank. Won't even turn over and the starter doesn't click. All the accesories die like normal when the key is turned to the start position, just no starter. Also tried jumping from my Tahoe, still no go. All the fuses are good, could it be the starter relay under the hood? How would I check this? :help:

When you turn the key to "START" does voltage drop at the batteries?? Also...when you turn the key to "ON" can you hear the click of the glow-plug relay engaging?? I suppose if you have a heavy duty push button switch you could jump the solenoid terminals to check the starter...but you said there isnt even a click (from the solenoid) so that probably means that the problem is happening before the solenoid/starter. Just some thoughts...

---Ben

Yes I can hear the click for the glow plugs. The Wait To Start light comes on, voltage drops like normal, WTS light goes out, turn key and.....nothing.

NSBU Switch>?
Try Cycling the gearshift lever a couple times, return to Park then try to start

Got Juice.
Thought about NSBU switch on the way to town today. Picked one up while there ~$160. The last time I moved it it was not started and in neutral. It does act like it's in gear and it is preventing it from starting.

I went to install the new NSBU switch, decided to try one more time and the SOB fired right up. Crap. I wish it wouldn't have started at all so I could troubleshoot without it leaving me in a bind somewhere. Oh well, give me time to order a cheaper NSBU from dmaxallitech and return the high dollar stealer part.

dangit. I hate it when that happens.

Hope you find the problem. Still sounds NSBU related, but keep us posted. Maybe check the contacts on the Switch???? Corrosion?

Well, at it again. This AM went to start and same symptoms as before, no crank, no click. The tranny will go into 4hi and 4lo and the gear indicator is illuminated showing which gear i'm in. In the middle of a tropical storm now, I'll check it tonight if it clears up. The way it's coming and going, almost sounds like a bad ground or poor connection somewhere. Awful hard to take it in when it won't start..damn I don't want to take my Banks off either.

why would you need to take off the banks? are you still under waranty with an 02?

Did you bypass the Banks?
Sometimes harness boxes act up.

McRat
I did bypass the Banks as step #1. No help.

ssduramax
I have 64k miles on '02, so yes I am still under the motor warranty for 100k, and injection system 200k.

Do you have an aftermarket alarm, or did the truck have a "anti-theft" gadget in it?

McRat,
No and No. Only the 6gun, Prodigy and CB as aftermarket electronics, all have been installed for over a year with no changes.

The reason I mentioned it, is because my 05 didn't crank after I did some work to it. Plenty of juice, no codes, nada.

Found an undocumented module under the dash panel which was a dealer installed theft deterent device. While I did not touch it, it suddenly became of concern because it tapped into the yellow starter wire. I cut it out, and she started right up.

You will probably have to put a trouble light on the starter and see if it's getting juice. If it is? Starter. If not? Uh, err, well something other than the starter!

Came home today from work and it started right up....again. Went ahead and replaced the NSBU switch. Easy to do except it was a real pain getting the two connectors off the switch. They had what was like a epoxy on the connectors and I had to pry them off with a large screwdriver. There was some tranny fluid that came from somewhere soaking the switch, maybe that had somthing to do with it. We'll see in the morning.

Nope. No go. The SOB Censored would not start again this morning. It acts like it's on timer. I hate electrical problems.-:t

Try to start it, if no crank, then hook jumper cables directly to starter. Clamp one lead to the starter and "tap" the other one to ground, with a glancing blow, and see if the starter moves. If it doesn't, new starter time. If it does, then try something else. Maybe a bad ignition switch.

Could you have an intermittent problem with the electrical connections or harness to the NSBU switch perhaps?

Precision37
I'll try that when I get home, if i can even get to the starter without taking a bunch of stuff off, I've never looked.
Lakingslayer
It's got to be a poor connection somewhere, just got to find it.

The bad thing is that it looks like a hurricane is headed my way and I will need to get my 5er out of here before it hits. I'm just a little north of Hattiesburg, MS and the state park I'm in has lots of tall pine trees around the sites. NOT good.

when it acts up check for voltage at the starter(purple wire)with the key in the start position.if no check the starter relay,if relay is ok suspect wiring or connector problem.

This is going to be a big picture, can never get them to resize

http://service.gm.com/engif/000/000/776/776446.gif

Thanks Cobra and p.hinds. Replaced the Relay Block-Body yesterday, and that seemed to work. I had 12V from the ignition switch to the relay block when the ignition was turned to Start, but nothing to the starter relay, I just replaced the NSBU switch so I figured it was a good place to start. This morning again...no crank. No power to the Starter Relay. I can't help but think it's something in the NSBU not passing the signal to the Starter Relay. I guess once it warms up, I'll have to take it in to the experts. They'll probably find the problem in 10 minutes. Just to be certain, the Relay Block-Body is the one under the drivers side dash with the fuses...correct? The relay I replaced seemed to disable the accessories and pass 12V to the Fuse Block-underhood.

the relay block-body is the one by the left kick panel,the starter relay is in the underhood box.use that wiring diagram ,pull tha cover from the ubec and get to the under side of it.check of course in the start position power at c10 of c1 and f10 of c2 purple white wire.if yes check e and g of c2 at the pnp switch,this will tell you if switch at fault.if you have power then check f11 of c2 under the ubec.then d11 of c2 which is the purple wireb that goes to the starter.common poor connections are the connectors under the ubec,the female side will open and cause intermitant problems,hope this helps

p.hinds. Thanks again, just to be clear the ubec is the underhood box, correct?

yes

Great, i'll try it in the morning.

Alright, had it all set up last night to troubleshoot in the morning knowing it wouldn't crank. Pulled fuse block apart under the hood and left accessible, labeled wires I would have to check connections on. To make my troubleshooting woes short and to the point...I found the problem to be the CensoredCensored 10A crank fuse inside the cab. To make me feel more like a idiot, it was my fault. The fuse itself was the first thing I checked last week when it first wouldn't start, it was good. About a months ago I pulled the Banks out to bring the truck in for ABS light on, when I got the truck back the same day I reinstalled the Banks unknowingly putting the tap for the gauge lights(which slides into the fuse connection along with the fuse) on the 10A crank fuse. When the lights didn't work I rechecked my work and realized what I had done and put the tap in with the correct fuse, this was 3 weeks ago. When the tap is inserted with the fuse it opens the female contact up just a little to accommodate it. When you remove the tap, guess what? It leaves a not so good connection. What just baffles me is that it was good enough to work for 3 weeks, and then only not work in the morning time. Amazing. Oh well, live and learn. Thanks everyone for your help, especially p.hinds, Cobra and GMCSID.

its always something youve looked at 20 times,glad to hear you found it.