Please help - failure to crank

[budwich]

You probably need to be a little more specific about your details of your problem... ie. which fuses numbers have you tested and when (ie. with key on, key off, etc). Further, what vehicle do you actually have. Then, perhaps you might get "lucky" with some help. Basically though, with your key in on, you should get power to your ignition fuse (22 for a 2004).... if that doesn't happen (how are you testing for this???) then you don't need to do much else til that is resolved..... battery comes into your switch on RD/WH wire and leaves on PK towards the "run" power distribution.

Still further, when you key is on, are all your "systems" in your car operating (ie. dash lights, radio, etc)??? Then, it is unlikely that you have an ignition switch problem (although there are two "legs"), more likely you have an issue with your fuse block "tracks".

 

[shawnd450r]

You probably need to be a little more specific about your details of your problem... ie. which fuses numbers have you tested and when (ie. with key on, key off, etc). Further, what vehicle do you actually have. Then, perhaps you might get "lucky" with some help. Basically though, with your key in on, you should get power to your ignition fuse (22 for a 2004).... if that doesn't happen (how are you testing for this???) then you don't need to do much else til that is resolved..... battery comes into your switch on RD/WH wire and leaves on PK towards the "run" power distribution.

Still further, when you key is on, are all your "systems" in your car operating (ie. dash lights, radio, etc)??? Then, it is unlikely that you have an ignition switch problem (although there are two "legs"), more likely you have an issue with your fuse block "tracks".

ive tested all fuses not receiving power to crank fuse or start relay and ignition fuse in rear. Ive now replaced ignition switch and nothing also the ignition tumbler still nothing. had battery tested they said it was good and I was receiving over 12 to the fuse box. I tried to hard start the silinoid it just spins do to starter not engaging I think because its not getting power to engage it. im not 100% sure Im going to take starter off tonight have it tested but I have never had one lick of trouble with starting it so this came as a surprise when I started researching all the troubles people have had. im not sure where to go from here neutral safety switch could be bad but im getting reverse lights and everything as far as lights, dash, radio, everything works fine just no start. now when I got in truck and this first happened I think I left my key on so it tried to start like a dead battery start but now that I charged battery not getting even an attempt. so im a bit baffled by that. could my computer be fried I did have to change a pcm fuse?? ughhhh anyhelp would be great im 3 days deep in head scratching and research and Ive read my chiltons manual like a good magazine front to back, back to front........oh its a 2002 Trailblazer LTZ

 

[budwich]

forget pulling the starter... that is unlikely to be a problem. As I indicated, with your key in "ON", you must get "run" battery everywhere... that means everywhere that is supposed to get run battery.... fuse numbers help more than descriptions as then they can be correlated to circuit diagrams without "translation error". IF we are talking about the same fuse 22 (IGN E), then this fuse MUST get power with ignition switch in ON. So you don't have do anything else in trying to figure out about even trying to cause a starter to move... forget the neutral switch, etc.

Further exactly how are you testing for power.

OK... I see fuse 17 is the "crank fuse". It only gets is power during flipping of the switch to start..... so how are you testing this with fuse in the engine area and you trying to crank... got long arms...

Further this fuse / switch gets direct battery from fuse 34.

 

[The_Roadie]

ive tested all fuses not receiving power to crank fuse or start relay and ignition fuse in rear.

It seems simple, assuming you have the schematics. If you mean front fuse #34, it's fed with "B+" which is 12V straight from the battery. If that's not present, the fuse block or wiring to the battery is at fault.

View attachment 30056

 

[shawnd450r]

forget pulling the starter... that is unlikely to be a problem. As I indicated, with your key in "ON", you must get "run" battery everywhere... that means everywhere that is supposed to get run battery.... fuse numbers help more than descriptions as then they can be correlated to circuit diagrams without "translation error". IF we are talking about the same fuse 22 (IGN E), then this fuse MUST get power with ignition switch in ON. So you don't have do anything else in trying to figure out about even trying to cause a starter to move... forget the neutral switch, etc.

Further exactly how are you testing for power.

OK... I see fuse 17 is the "crank fuse". It only gets is power during flipping of the switch to start..... so how are you testing this with fuse in the engine area and you trying to crank... got long arms...

Further this fuse / switch gets direct battery from fuse 34.

ok so im testing with a multi meter and a test light I have tested all with key in on position and ones that don't have power have been tested under start load and if they still did not have power they were replaced and tested again. I would have to go after work to give you further details on numbers, locations, ext. im not much of a take it to shop kinda guy and this is how my ole man always taught me to learn so though im stumped im sure with little help from you boys i'll be able to hunt it down. I also read about the whole passlock deal but my security light is not staying on ohhh and my key is all the sudden not releasing out of the ignition this to has all come from the same exact time this all started. Thanks for the help in advance its much appreciated

 

[budwich]

not problem... I hate the $100/ hour shop charges to "learn" on my vehicle. As Roadie has posted, the circuit is pretty straight forward... you don't have top go into too much fancy stuff.... at this point it doesn't have anything to do with passlock or other wise.... yes those circuits come into play later but the conditions that you are measuring are as laid out... nothing else.... as you can see from the posted circuit diagram.

 

[shawnd450r]

Ok so got truck started 34 fuse thanks a million now how do I get it to run good again

 

[The_Roadie]

I'm still hung up on how you tested all the fuses and missed this one?

On the running poorly, is it driveable? If so, take it out for 20 minutes around town and see if it gets better.

 

[budwich]

yep... I see that a lot... "checked all the fuses and they are good"... that usually means they checked the ones that say "XXX for YYY function", etc... they don't actually take the "10 minutes" to actually check all the fuses. Anyways, it got "solved"... odds are that the "running issue" is probably from "battery disturbances" along the way and the ecm has to do some "re-learning"... maybe.

 

[The_Roadie]

Please don't take this the wrong way - it's not aimed as any poster in this thread. I've just been meaning to write this sort of thing for years.

Roadie's Guide to Electrical Troubleshooting

How to check Fuses
Good technique: Remove from fuse block. Use multimeter on resistance or continuity mode. Look for zero Ohms or listen for a buzzer indicating continuity
Bad technique: Look at them, not knowing what a good one versus a bad one looks like. Shake them. Roll them around in your hand like dice.

How to check Relays
Good technique: Understand what the function is of a relay coil versus the power contacts. What N.O. and N.C. mean. How to wrap a tiny wire around the blade of a relay so you can check voltage while it's plugged in. Know how to read schematics and command the relay to go on while checking its outputs. Or remove it from the vehicle and bench test it using clip leads and a meter. Exchange it with a known good spare or a probable good identical neighbor. Understand that some relays are not electromechanical but made from semiconductors that can switch silently and faster.
Bad technique: Take them out and shake them.

How to check lamps
Good technique: Remove them, understand how the filaments are connected to the connector contacts. Check with multimeter on resistance or continuity scales. Check the socket, with the lamp plugged in if possible, using the multimeter on the proper voltage scale. A test light *might* be useful here if you cannot afford the $4.99 for a cheap meter at Harbor Freight on sale. Test lights are USELESS on jobs that require you to check resistance or continuity.
Bad technique: Take them out and shake them.

How to check connectors...switches...long wire runs...grounds...batteries...etc.
More of the same.

 

[shawnd450r]

Yes yes my apologies I saw the ignition fuse 36 and neglected to check 34 outta mistake I took it to get codes read and that's a whole other ball game as soon as I got to road and hit thirty engine light started flashing, slowed down, light went solid, sped back up flash again. luckily truck was close to advanced auto. they read codes to me all 15 of them, yet only one was current cylinder 5 misfire now as far as the others listed under history is this possible that when I bought from dealer last year they cleared codes I've never had check engine light come on since I've owned but there were all kinds of rediculous codes that I've never had issues with. And I'd like to add before this all happened it was running good or so I thought so with it running so terrible now does that mean that truck was actually dealing with it on its own and by the way thanks for taking time to help me I know I'm no mechanic but damn it feels good to fix something for 3.99 instead of 399.00 thanks guys

 

[The_Roadie]

Bad plug or coil on #5 would certainly give you crappy driveability like that.

 

[budwich]

Interesting, Shawn... "now we know the rest of the story"....

You will note that your post is under "please help- failure to crank".... "failure to crank" has little or nothing to do with "running bad"... of which, IF you have "codes", they may or may not be an indication of an issue. Specifically addressing that particular issue with some troubleshooting is probably wiser than hoping is will be addressed with a "relearn" especially if the "relearn comment" (mine) was based on not hearing the "rest of the story" before it was made.

So if your truck is still running badly, you have an issue that should be looked at before it becomes major and your $3.99 becomes $3999... :-(

At the very least, get your codes read again. Further, probably start a new thread or search for a more appropriate one that can better describe "not running well".


PS.... Roadie, nice writeup on testing of fuses.

 

[The_Roadie]

Ok so got truck started 34 fuse

Admittedly it was for the original, ORIGINAL poster of this thread, but I called it in post #5.

 

[xj2202009]

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