No-Crank Chevy...NOT What I Expected!

This 2003 Rusty Chevy Silverado has been intermittently refusing to crank the engine. But now it seems COMPLETELY broken...and also the battery is dying overnight!

Place your bets now...corroded ground? Rodent damage? Blown fuse? Could be ANYTHING!

Let's follow the wiring diagram and a logical approach to pinpoint this issue. The root cause was not expected at all...

MAGIC TEST LIGHT:

THINKTOOL PROS:

ASTRO DVOM:

ASTRO DC AMP CLAMP:

Enjoy!
Ivan

[tomsawyer]

Exactly my problem on a 2004. I couldn't find a wiring diagram, took it to a shop twice. First time, he replaced the fuse box. This must be a common problem with the fuse boxes. A year later, same problem came back. I was using a jumper wire to start the truck. I applied your fix, and bingo, problem gone for good. Thanks a million.

[skillz]

As a diag tech myself.... This guy is extremely good.

[JWezley]

Dude, you rock. So hard to find logical quality diagnostic individuals on here. Thanks for this.

[rebelsoul]

This wire ended up being my same problem. After 3 years of intermittent issues. No crank, sometimes with instrument lights, sometimes without, except the check engine light. Intermittent blower motor function. Random dimming of lights. Even my 4x4 switch issues. Thank you for this excellent video!!!

[crisprtalk]

Every video I am amazed that Ivan does all this stuff mostly one handed. Incredible.

[billziegmond]

Wiring diagram circuit understanding and logical thinking. Add Eric O's favorite tool a scope on rope, Problem found. Finish with Ivan's no parts required. Car now fixed. Bravo my friend.

[rick]

I just found you a few days ago. And am I impressed. What a teacher. I have been a Shadetree since the mid-seventies. I do pretty good but have friends in the business I would have to call if I got stumped. Being schooled by you and how these lessons can be used for all kinds of problems is fantastic. I thank you for what you just have and will teach me with each posting. Keep them coming and again, Thanks.

[arcburn]

My grandson had to wiggle his headlamp relay more and more often to have headlights on his '99 GMC 1500. When it got useless, I bought a fuse box off a Tahoe on Ebay for $30. The listing on Ebay had really good pics and I could tell they were a match. It was loaded with fuses so we ended up with a lot of fuses and relays for parts. Cheap fix. I told him to notice when an oncoming vehicle had a headlight or daytime running light out, it would probably be a GM product. He laughs every time he sees one now. Great video Ivan!

[keltecshooter]

I started using a notebook years ago because of this channel, its also helpful with cars that have similar issues and I have a record of what was tested for myself .Service writers will never include that kind of information and customers will return when the check engine light is back on and only assume its the same exact problem.

[JWezley]

Thanks! You are worth so much for what you are sharing. I don’t subscribe to anyone, but I will for you. What you do for the auto repair community is in a different category than everyone else. Thanks for being you and sharing.

[lowerider]

I have seen this problem before as a Chevy tech. I was like he is going to go straight for the ignition switch fuse cutting the system in half. As my mentor always said to me. I don't care how long it take you to get the answer. As long as you get. Good job.. push to be like you one day.

[JoseSilveira-newhandleforYT]

Great diagnostic, Ivan! I would go straight to the ignition switch, because it's a high wear part that can fail, but didn't expect the problem to be in the fuse box - good reasoning and not jumping steps really paid out! That corrosion control device seems to work well for itself - the device is not corroded :-)

[GaryB]

Congratulations on 150K subscribers. Well deserved.

[richardsedillo]

YOU ARE A BAD ASS TECH YOU ARE A TEACHER IN OUR WORLD THANKS RICHARD

[pakjohn]

The Master at work. Always interesting, always informative (if you are a diagnostician)

[walterbordett]

Great diagnosis, Ivan. You are right about keeping notes.

[htownblue]

I absolutely love this case Ivan! It shows how a simple tool Adam be used and applied in strategic manner to diagnose what would be a parts cannon nightmare. Mad respect for the NPR King Ivan the Great, First of his Kind, From House Diagnostic.

[TheDervMan]

Fascinating. I’d love to see inside that fuse box.

[georgegonzalez]

A theoretical mathematical point: You can do this kind of detective work MUCH faster if you use a binary search algorithm: pick the midpoint of the circuit, check it. That cuts the search area in HALF with just one test. Repeat halving and testing. For instance if there are 8 points of failure, instead of having to test 8 places, you can find the problem with just 2^X=8, where X equals 3. If there were 64 points, just 6 tests. Theoretically proven to be the best search algorithm.

[SouthernDevilDog]

This video helped me greatly. I found the B12 wiee on my fuse box melted once I checked for power. Spent 3 days checking wires, replaced the starter(it was bad anyway) and replace the ignition switch. Thanks for the detailed video.