Two things: 1. I believed (incorrectly) that the circuit was loaded by turning the key on, most PCM ignition feed circuits are! I did NOT forget to load the circuit. I was just wrong in that it wasn't loaded. 2. The .9 volt difference initially WAS too much! BUT I had tunnel vision from what the customer told me and that was this problem WAS NOT there until that multi-function switch was changed. My mistakes made for a great teaching video though right? :-) thank you all so much!!

Great point about finding a trustworthy shop like Danners. My son lives in Ohio had a reduced power code and repair shop wanted to change crank sensor and starter, plugs, and fuel system clean. $900. Since I have been premium subscriber and Paul is such a great teacher I had confidence to troubleshoot myself . Ended up being a wiring harness chaff at throttle body. Cost me under $1 to fix. Thanks Paul for being a great teacher. Calab great job editing!

When you said at the beginning that you had not brought your test light, my first thought was, this is why the video is over an hour. Lol. You and Eric O at SMA have drilled it in my head to ALWAYS load the circuit. Thanks for the great videos sharing your knowledge.

You didn't check the voltage under load but you were watching the O2 heater current and recognised that it was low - that was the second clue after seeing the 0.9V drop under standby current. I've been an electrician long enough to understand exactly how these things happen, even to the experienced. The nice thing about your mistake here is it added a lot more educational value to the video! 🙂

I had this exact same problem on my H3 no one else know what to do they all said to replace the throttle body or look for a shorted wire your the only one who got it right all I had to do was pull the relay clean of the pins and put it back thank you so much.

I appreciate the fact that you will show where you may have missed an opportunity to prove something and go back to do that. Awesome, guys.

The last two minutes with the test light are pure gold. I (mistakenly) used to think test lights were for dummies and the smart folks had/used meters. Thanks to ScannerDanner Premium I have been reformed. Now the test light is at the top of the tool box and the meter rarely comes out. Until ScannerDanner Premium I never knew how valuable the test light is. From spark testing to circuit testing...I use it for everything now. I even have a few headlight bulb pigtails for the bigger stuff.

As an automotive Electrician I have learnt a lot from you Danner and my confidence had grown so much. Thanks Paul.

Caleb, you're doing an amazing job with the editing. Especially when it's "Fun at Dad's expense" at the closing. I'm gonna spend the rest of my day with Paul doing the mission impossible theme in my head too. Make that a ring tone, I'd buy it. :D

I have seen this video before, but it came up in my feed so I watched it. What I found interesting was the flowchart said to use a test light which you and Eric O always comment on how the manufacturers do not do the simple tests. But yet, here they did and it would have given you direction. Great learning experience though. I always enjoy your thought process. In this one you kept struggling with going to the PCM you knew something was not correct right where you were ... but you did not know what it was. Once you moved to the computer, it brought you right back to where you were. Paul, thanks as always.

Absolute gold again! Easily the most in depth content online. I was talking with a friend yesterday and we agreed that the fact the videos show the whole process, even the learning curves makes you the absolute king of diag! Testing things more than once in different ways to prove the point is key! Thanks Paul. I'm signing upto premium!

In this case, the flow chart was well-written when it recommended probing each side of the fuse with a test lamp. I've learned that any voltage drop at or above 0.5 volt is considered too much; 0.3 volts is acceptable, but anything above that is cause for concern.

This was the first video I watched on your ch and I have so much respect for the process, the fact that it took you as long as it did and not edit out mistakes is more valuable for a DIY guy like me. Thank you

I agree on the economics of electrical fuse box replacement vs. cleaning in a commercial shop environment. And I agree that for the individual, cleaning may make sense. Case in point: My brother has a 12 yo 4 wheeler that the ignition switch would make/loose contact without warning. He asked me about it and I sprayed it thoroughly with Deoxit D5, rotated the switch key a couple dozen times, sprayed it again, rotated it a couple dozen times again and it has worked flawlessly for 2 years now. So, in this case, it made sense. By the way, I've been using Deoxit D5 for quite a few years and highly recommend it for these situations. Thank you so much for sharing your VAST knowledge with us! I learn so much from you!

That's exactly right, there is a definite shortage of "diagnosticians" in the field. Compounding the problem is that finding them takes a lot of work, time, and money! Not only that but it gets kinda weird when you go to a shop and ask the owner if he has ever used a PicoScope - and he just looks at you like you're from outer space! lol Thanks Danner family!

Very good video. I have a 2006 H3 and belong to multiple Hummer forums where this TAC/ECT has been an issue many times. Unfortunately, these fuse boxes have a problem with corrosion. Great job on finding the problem.

Awesome video! I too own thousands of dollars worth of equipment, but sometimes your test light and knowing when and how to properly use it is your best friend. Thank you Paul and Caleb.

This demonstration how important loading the circuit is was awesome. This turned a 2$ testlight in a high performance diagnostic tool. Thanks for putting the old relais in again and demonstrating the results.

Unbelievable! I'm living on another side of the world in Riga, Latvia, and I'm driving the same H3 2006 ... had the same issue P0601 ...was looking for a problem, can't find a problem ...NOW I KNOW ... fuse box and relays and RUST ! Thanks to you guys for this video !

This type of problems always takes us back to the basics! start with a test light!! 30 years doing it and never fails!*!

I just wonder why there are 23 dislikers to this video! this video is full of heavy information and you brother are doing the incredible job just to get these information passed to us as good as possible. So you deserve more than just likes.

Great video Paul! This is such a great video showing the power of a cheap test light and loading the circuit. Goes to show you Don’t always need the expensive tools to diagnose a vehicle. Key point is loaded circuit testing here! Great demonstration of voltage drop. Great work!!

This is an amazing relationship between dad and son that’s a strong bond and Caleb is going to be a beast auto mechanic Thanks to dad who needs a auto mechanic degree when you have dad teaching you

I had to smile when you said you were confident, then corrected it to fairly confident. Confidence is the feeling you sometimes get before you fully understand the situation.

I’m just a DIYer but following your book and KZfaq managed to diagnose a very similar issue in 15 minutes!,,, thanks to your excellent tutoring. My buddy was well impressed and I’ve directed him to your site. Awesome stuff - you must have helped thousands of us by now.

You may notice when you have a video posted it takes me a while to get here. It's because I want to be in a place that I can be focused. You provide so much information that I want to be sure to have the time and place not to be interrupted or distracted. I truly look forward to your videos as they are not only informative but entertaining. The lessons here are many but the thought process and how to decide on a "direction" is instrumental in my own diagnostics and repairs. Thank you again for providing such good content. I hope you and your family had a fantastic Thanksgiving.

Always good to watch the Danner family. Really glad Paul that your bro has got a shop and you and Caleb can go there to film.Thanks as always.

That was a powerful message how not to change parts based on codes!! Great choice of troubleshooting paths- you were spot on not worrying about that multi function switch, and sticking with what you knew was true!!

Phil was my automotive instructor at a community college Mt San Jacinto, Ca all the way back to 1980's

Paul I have seen very similar to this on some Yukon and Chevy trucks. I found the bad relays by looking at freeze frame for ignition 1 voltage, which was zero at the time of the fault. I totally get how the customer can swerve your diagnostic path. Been there and done that brother. Thanks for what you do to help our industry.

Great case study Paul! I love all the videos coming from your brother’s shop!

Common with the fuse boxes to corrode internally and luckily new ones are not that expensive and are readily available. Great job as always and glad you went back and showed what it looks like loaded so people can really grasp the importance of a loaded circuit

So cool that y'all can work together and have real fun doing it as a family . probably very rare .

I thought I was an OK automotive diagnostition until I started watching SD. Now I question all I've ever known about the Universe. Thx.... alot!

Great job, Paul. Shows the importance of voltage drop testing and not discounting even a 1V drop and also being thorough and revisiting test results that aren't making sense. 🤘

I was just preaching the loaded circuit testing that you’ve pounded into my head over the years to the young guy that works for me Friday. Great vid.

you are a great teacher because don't hide your mistakes. We all make mistakes on the field but just the greatest admit them!! I always learn from you

I am a fan of this channel because the diag is awesome. I play these videos in the shop like music. You can learn pieces of valuable info while listening

This was a great look into system operational theory and diagnostic steps. You provided substantial educational diagnostic information leading to root cause later followed by seasoned technician steps with quick process of elimination using your test light. Thanks for taking the time and showing both methods arriving at the same conclusion - a lesson in and of itself. Great job also with the filming and editing - like the graph/video overlay!

We've all been bitten by mistakes like that. BUT! You found it! Good Work!

Yes the battle is people who know there stuff and people that don't! Don't sugar coat it Scanner! That's why I subscribed to the channel. It helps me get a better understanding of how to familiarize myself with testing wiring and circuits. Great channel!

Excellent video Paul,James and Caleb. The dynamic Trio at it again. Man I think before anything from here on out I'm going to check every item in the circuit for corrosion. So many faults for the green crusties and corroded wires. Manufactures have created so many areas for corrosion to form while leaving out water intrusion control. Poor manufacturing and making every item a throw away part. Without protection and quality control systems will fail and quickly. Spend a year on a Naval Ship and you learn what corrosion can do very quickly and how to prevent it. Good video guys 👍👍👍

Damn Danner how many times I heard from you no current flow no voltage drop and you missed it, I was yelling at tv when I saw that 1 volt difference, And my girlfriend laughed at me when u said it wasnt a problem, for it to come back and be THE problem def made my day!!! Love u buddy great videos, keep that passion to be the best I know it's hard sometimes and easy to become complacent

I’m a parts changer I admit that’s why I watch this videos trying to learn from the best 😂

I also face similar problem on Chevy captiva 2007. It took weeks to find the main relay was open . Thanks for your training videos.👍

another fantastic approach to solving an apparently related issue with the replacement part, thank you.

You said way did you not put a load on it either way PUAL you still fix it and you told us to put a load on the fuse the right way no one is perfect. Thank you for the lesson

Diagnostic tec here for Audi. Just wanted to say thanks for all your amazing vids been subscribed for years and when I was a apprentice learning your videos where a real help :)

Awesome content Paul! Been a premium member since your scanner Danner premium channel on KZfaq began and continued to be on your website! Not planning on canceling anytime soon. AVI on demand charge over $100 per video for 1-3hr content on many videos, it is very good content I’m not going to lie but yours is as good as theirs and with 1 purchased video from avi you get a whole year subscription at your premium site! Can’t beat that infinity times! Lol. Thanks to you and your online class I’ve been able to diagnose cars even “technicians” with “years of experience” haven’t been able to diagnose. All credit goes to you Paul! Thank you!

Good skills. Don’t be hard on yourself not fixing it within 5 seconds as we learnt a lot along the way in the process and then how to do it quickly afterwards! So all was not lost. A great lesson for the owner too and of course a little one for you too in the best way around to look at a fuse box and diagram! This video sure made me smile at the end and I haven’t done that for a good few days. Oh and sorry final point got to give credit to Caleb too with the quality of the finished product

Yes, we can’t believe that customer voice every time.we want to believe our selfs as a technician 😎💯🔧

Love it man! Taking it nice and easy, its extremely easy to lose track of the steps with that much going on. Especially not getting the full story from customers. Keep it up.

Dude... I have been trying to figure out this problem for years. Mine is intermittent and if I reset the codes it would run but lately has been more frequently. Thanks for the best video I have seen yet!

It is awesome to see Danner rocking it in his new shop! Thank you scannerdanner for doing what you do every time I watch your video's I learn something new for that I'm grateful I own your book and I love it!!!

Hello from Saudi Arabia you are best diagnostic teacher in KZfaq 👍👍

Great fun guys, Jim can always get me to howling though. I do miss the days when he was posting, but life is what it is, ya have to roll with it sometimes.

my master diagnostic tech. doing what he does best. Great video

preconceived ideas, avoid them. have had that beat into me over the years. Haha I was a heavy equipment diesel tech with some auto knowledge from my college days. I now farm and work on my own stuff if I have time. I watch these kind of videos for entertainment and education. Thanks for posting them.

I had an 06 h3 in the dealership not to long ago, another shop was shot gunning parts at, new throttle body, new air injection check valve, new o2 sensors, had the dash half torn apart, new fuel pump, I actually found it pretty fast I,E. I got lucky, was checking checking fuses and relays, kept losing and regaining power on my two fuses that powered the throttle body and the o2 sensors, pull the relay, crusties everywhere, pulled the block, corrosion beyond repair without replacement, beings I work at the chevy dealer, we actually see corroded fuse blocks allot, they always cause scratching your head problems, now one of our first things to look at is the fuse blocks.

I dozed off some the first time I watched this video this afternoon and, watching it again, I made some observations. If I'm engaged enough and have time for it, I'll participate vicariously at home and pull up everything you're looking at in Identifix if/as needed which kinda fed some of these observations. Honestly Paul, I'm glad you made the mistake so I could catch them and point them out....Silver linings :D First, I noticed something off while you were initially testing fuses at 46 & 47. The wiring diagram showed a 15 amp fuse for ETC fuse 46 and a 10 amp fuse at the O2 fuse 47. Both the fuses you tested were 15 amps. I thought I caught you in another mistake, but the mistake goes to Mitchell. I found a copy of the underhood fuse block label in Identifix and it shows them both as 15 amp fuses. I also reread the flow chart as printed in Identifix and steps six, seven, and eight as printed in your info flip flops between labeling that circuit ETC and TAC whereas Identifix just labeled it "Ignition 1 voltage circuit" through all three steps. At about 39 minutes into the video, you're trying to ID the right PCM connector. You'll notice that the connectors are grey, black, and blue. GM uses those colors as additional connector identifiers and Mitchell wiring diagrams USED TO include those colors with C1, C2, C3, etc... For those that may want to try and figure out which is which without pulling a connector, any good service info provider should still be able to show you that correlation in "connector views" and I see that OE wiring diagrams will still label those colors accordingly. This might be good to know for those of you who spend a lot of time at BCM connectors. GM loves to run a funky rainbow of connector colors at their BCM's. I thought these things worth bringing up to show the DIY'ers what they're up against when they go into a job without much more than a can-do spirit. Luckily, none of these shortcomings in the service info was of any real consequence; but it can get much worse. Even for the educated in the field, you're fighting bad information that can hinder diagnostics and repairs. (I have plenty of days that I'm happy to trade Identifix off for a crap shoot on Google or KZfaq. If you have to settle for Google yourself, just be wary not to use it as an enabler to load the parts cannon.) Having said that, I'm dying to know where I can find an English to rational English translation of Mitsubishi's factory service info. And lastly, that Scanner Danner/Mission Impossible ring tone actually needs to happen. I'll gladly dip into my beer budget to buy it.

В нашей работе всегда так, пол дня ищешь причину, а потом смеешься с того, какой простой она оказалась. Отличный урок, спасибо.

Wow.! This is another fantastic video dude.I got a tear in my eye watching this as the diagnostic timeline developed ,,tears of joy that is :) And i heavily agree with you on the importance of changing peoples view on how to really attack an electrical problem..and not just go ahead, reading faultcodes, and changing parts accordingly.Im a strong believer in doing proper diagnostics ,like you perfectly showed here..even though you "missed" an important step like you said,but that stuff can easily happen..The cool thing is that you KNOW that you missed it..and with your fantastic knowledge..you were able to use that info,,and verify what you allready found to be the culprit.I bow to thee,dude.Thank you for a fantastic video,and thank you also to your cool son ,that is making these videos into even more diagnosticvideogoodness :) Greetings from theNorwegianViking,Stefan :)

More great content from the Danner brothers. You guys rock!

you are the best the king . I learn a lot of stuf from you ...honestly I learn every thing about cars diagnostic from you so you are my hero man .

Brilliant training video Mr Danner, thank you, Sandy

Great job Paul, and Caleb editing and camera work is awesome too.

You are doing a great job in saving the industry's reputation. Here in AZ, we have a lot of parts changers and when I say I will charge them for a diagnostic; customers get all defensive. They believe every mechanic is out to get them

Great video! I have the exact H3 model and have done almost everything to it to "freshen it up". Plugs, coil packs, cold air intake, cleaned throttle body, all new fluids, thermostat, and belt. Runs good but feel like it idles a little rough and can run a little bit better. Will check out relays and then most likely take it to GM to get diagnostics ran on it... just want it to run the best it can.

@ScannerDanner I'm like...when is he gunna put his test light on that fuse with the suspect voltage, and mmm, no volt drop tests yet?....Oh well, maybe we're just leading up to some fandangled new testing approach....always good to know some of that, kept watching thinking 'I wanna see what we get if he puts a test light on that fuse with the voltmeter or scope connected'....keeps watching.....great 'drop ins' from Caleb, and awesome follow up at the end😜👍...Lol. Love your book and all you're vids Paul...You really are changing lives around the world😜🤣 Thank-you from Aus.🇦🇺

Relay # 81 was the culprit I spent days trouble shooting and replacing all kinds of parts. Do your self a favor if you have this issue " Reduced Power / Traction Control SYS Stability " get an ohm meter pull your cables and use alligator clips to check the relays and ohm resistance.

Just got the Book Today , I will be reading and learning trying to get up to Speed Thanks

You are my new favorite channel! I am going to assume that you arent familiar with H3’s, you have alot of common since questions that your experience cant answer, well welcome to working on a Hummer. Electrical demons and nightmares are everywhere in these things. Good find on the relay!

Sure glad you didn't cut out all the boo-boos when making test equipment connections. Was thinking I was the only one that did that. :)

I've smoked the entire video, that was awesome Paul💪

As usual you have been great, I always learn a lot from your videos, a small problème a corroded relay, no one could believe it. Thanks a lot

Thank you! Danner family you guys are awesome!

You should make this a soundtrack and implement that in ALL Your Videos - "Detective Danner and the Problem of ........the faulty Relay...." *THANKS FOR SHARING* Great Editing Caleb !!

Looking at the end of the video about not checking the circuits when they are loaded. I wouldn’t beat yourself up about it. We can only go down one road at a time. The important thing is to go down the right road at sometime. Now if you contact The Gods and request a clairvoyance package, I don’t think Snap-On do one yet. Haha. Kudos to you for showing no one is infallible. Regards, Peter A.

You are very patient with your son. Good for you!

Sorry for spamming your comments, but I just had a great idea. You can get these little mini 3 digit digital volt meters 0-30V for like a dollar from china on e-Bay. I am going to take a HF test light and put a volt meter before and after the bulb in the handle. I can put in a small bridge rectifier so I can power up the meters in any polarity, and then put bi-polar dual color LED on it to show the positive or negative voltage. It will be the best of both worlds, dvm before and after a load. I will have to do a video on this!

Great work Mr danner, it doesn’t matter if it could’ve ... would’ve ... taken 5 minutes, 50 minutes , 5 hours , who cares it was fixed , regardless the customer will pay and be happy , I work in the heaver vehicle trade with can systems etc with non start vehicle sitting off the road for months with everyone having a go at fixing them , there’s nothing worse than having to look at a vehicle with 5-10 previous mech/diagnostic guys having an attempt but no success , all I can say is great work and I enjoy your work 👍🏻

Gotta love the friendly banter. Now if I can only get that theme song out of my head!

After watching that video my $11 a month was well spent Great job.

Nice video overlays Caleb.

You are THE best bro. I can make a living learning from your videos thank you and my God bless you bro.

Nice work Paul at least you still fied and in the long run that all counts man great video i like the way you go threw all the steps to get to the problem.... thanks

Wow.Yeah you can have a lot of experience sometimes it can lead you the other way.Always learning is a clue.

Great job...a test of patience and determination!

Amazing video. I learned so much. It is for certain that shops need more diagnostician and just replace parts. How can I get certified as diagnostician. With this pandemic I rather change career. It is amazing the way you tackle these tedious problems with positive attitude and you make seems the repairs easy. Thanks

Caleb, I thought the same thing about changing positions immediately 🤣 but your dad does have a point, in his fixed stance

Excellent video, we never stop learning,

Who would of thought that .9 volt difference would make that big deal. I guess another thing to watch for. Very good diagnosis. Have your book which very helpful.

Great Video! Great example why to double check your testing method. Thanks for sharing.

Well done here. I certainly learned a lot on this one.

in a round about way you made that so easy to understand for me anyway, thanks.

You figured It Out without Throwing Parts At it. It's A Win. Us Who work on Multiple Brands Can't remember Everything

Well done good sir smooth as ever

A local junk yard cuts the harness and fuse boxes out of all the cars before they crush them and they throw them in a big dump truck bed. The other day they told me I could have all the fuses/relays and pigtails I wanted. I was out there in the snow for two hours with my wire cutters like "There be gold in this here truck bed!"

Always the best experience to watch your videos, best learning experience, thanks a lot.

I wish Danner would let me use his shop when I need a space. I'm here on the gravel and using a cardboard box as a mat :(