2017 Chevy Express School Bus - No A/C! Diag & Repair!

We have here a 2017 Chevy Express Mini School bus, which the A/C does not work. The compressor is not engaging, and it has something to do with the aftermarket parts. Watch as I struggle to figure out what's happening without Diagrams! Enjoy!
#diagnostics #mobilemechanic
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Disclaimer:
Due to factors beyond the control of Advanced Level Diagnostics, I cannot guarantee against improper use or unauthorized modifications of this information. Advanced Level Diagnostics assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Use this information at your own risk. Advanced Level Diagnostics recommends safe practices when working on vehicles and/or with tools seen or implied in this video. Due to factors beyond the control of Advanced Level Diagnostics, no information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. Any injury, damage, or loss that may result from improper use of these tools, equipment, or from the information contained in this video is the sole responsibility of the user and not Advanced Level Diagnostics.

[@craiggoodwin9704]

I learned two things from this video. Read those diagrams until you are "blue" in the face and......never work on a bus! Thanks for Sharing! 🙃🙂

[@advancedleveldiagnostics]

💯 Well said!

[@Hybriddiag]

Without diagrams its hard but you nailed it bro ...just proved your understanding of logics how system works...cheers

[@advancedleveldiagnostics]

Thanks!

[@steveo6631]

Wow, we didn't have A/C on the buses when I was kid... Let 'em suffer like we did.... LOL... You have perseverance, my friend... Regards

[@mandytuning]

Wait, school bus? I have to walk under the sun or storm for milessss

[@steveo6631]

@@mandytuning I know, and it was uphill both ways.... LOL

[@advancedleveldiagnostics]

Lol that was my first reaction too!

[@Wayne-p7n]

Really, what's up with kids these days? I remember we didn't even have lunch rooms

[@glenforehand]

I'll never understand how a shop wouldn't have service data but there's 3 local to me. Needless to say it helps my business out. Great work as always! I love that Veto bag. My new Flex tote is working out well too.

[@modernageauto]

Fun stuff. I used to work on Sprinter-based ambulances and doing anything without diagrams from the upfitter was nearly impossible. I don't miss those. Good find, man!

[@advancedleveldiagnostics]

Thanks!

[@globalcommerce7654]

LoL I did a AC on a school bus just like that a few weeks ago! was a different problem though, wiring going to fan under the bus was cut in overhead compartment, I've still got to edit and post the video, good work as always 👍🏾

[@advancedleveldiagnostics]

Thanks! Looking forward to your video!

[@glenforehand]

I'll be checking that video too!

[@8power0]

THAT WAS OUTSTANDING WORK ,,,,,,,,,,,,, I COULD OF SEEN MYSELF WALKING AWAY FROM THIS DIAGNOSIS MANY TIMES WITH NOT A CARE IN THE WORLD . NO WIRE DIAGRAMS AND SOMETHING I AM NOT FAMILIAR WITH HAVE A NICE DAY .

[@advancedleveldiagnostics]

Thank you!

[@jefftovani5535]

You work on school buses as well,cool,get it cool,lol!! Thanks my friend great content as always!!

[@advancedleveldiagnostics]

Only when they bother me enough to work on them, lol. Thanks for watching!

[@Nemesis-yn5wv]

Must have been frustrating. Thanks for the video. Never fun without the diagrams. Especially with that many splices and butt connectors.

[@bartscave]

Your diagnostic skills amaze me every time. Thanks for sharing.

[@advancedleveldiagnostics]

Thanks!

[@Jursaw]

Wow, a lot of work just to find that broken wire! Next time I bet you will request the wiring diagram before taking the job haha good job!

[@advancedleveldiagnostics]

Yes for sure!

[@billmonroe8826]

After market sh*t always is frustrating, especially if there is no diagram or it was done sloppily! Nice work but I'd charge for every hour just because you earned it!

[@advancedleveldiagnostics]

Thanks!

[@bobbywarthan5173]

Once again i love you thought process when diaging vehicles

[@advancedleveldiagnostics]

Thanks!

[@mikedavidson2117]

Hi good thing you are consistent and didn’t give up

[@PaulCTownsend]

I think bluebird bus outfit could help you with the diagrams and stuff like that.

[@djosbun]

Excellent work, Lazer! 👍🏼

[@advancedleveldiagnostics]

Thanks!

[@paulspeller968]

old school my friend . poke and hope . follow the money and sometimes you get lucky . what does it need and what’s missing . theses jobs can turn into days without service info . you know you will get there. it how long it takes is another story . plus tough one to explain to a customer. 8 hours diagnostic and 10 min fix 🤪🤪🤪 story of my life back in the day 🤣🤣🤣. by the way awesome job buddy 👍

[@advancedleveldiagnostics]

💯

[@nv1493]

Great work! Just fyi, on the express 6.0, the oem thermo engine cooling fan works well. Aftermarket versions as expected are junk. Not related to outfitter school bus wiring that you fixed, but there's a main harness feeding the ECU (driver side fender) that often sags and rests on the control arm. Ends up chafing thru the plastic loom and into wiring. Can be overlooked at a quick visual check because its underneath. Lifting the harness will show any damage. For weird electrical issues that's the first place I check.

[@advancedleveldiagnostics]

Good to know, Thanks!

[@jmanatee]

Crazy what aftermarket stuff does to a diag

[@NoName-yr1jv]

Well done 👍

[@jcc3279]

it's actually Chevy Express Chassis with a Thomas School Bus Body. for wiring diagrams for the bus body part you'd have to get a hold of Thomas built buses or wherever made the bus body

[@LRJPROPERTIESLLC]

Good job, learning alot from your skill. Thank 🙏🏽 you.

[@advancedleveldiagnostics]

I appreciate that!

[@MILKMAATTERS]

Great video

[@advancedleveldiagnostics]

Thanks!

[@moeitan4505]

What brand is the scope you are using?

[@hxc7273]

Aftermarket modified vehicles are always a trip to diagnose

[@advancedleveldiagnostics]

💯

[@MuridHolyBEEP]

Weird question here, I believe I've seen a video of you using a break-out box before but I can't recall which video it was. I am trying to learn how to use a break-out box (when to use it and how to use it and if scoping is the only way when it comes to break out boxes) I've only recently started doing electrical diagnostics and am fairly new but I've been learning a ton watching you work your magic

[@advancedleveldiagnostics]

All a break out box is doing, is giving easier access to the pins in the data link connector. I use it most often for checking the ohms of a can network, and I also scope the can network there as it's the easiest place to check at. You don't need a scope, I just find it helpful on network diagnostics.

[@MuridHolyBEEP]

@@advancedleveldiagnostics thank you boss I've been trying to find some KZbin tutorials on how to use the break-out box with the multi meter (what hooks up with what ) I use michelin 1 but they don't provide specs a lot of the times so it leaves me blank on whether what i'm reading is good or if there is an issue

[@gilron9585]

There should be a sticker of the a/c company who did this bus on the rear a/c box so you can approach them

[@donaldboyett2571]

I seen this problem when you showed the pid for the high side pressure switch. It was reading low

[@donaldboyett2571]

When you first looked at the hvac data

[@advancedleveldiagnostics]

The High side is a Transducer not a switch, it was reading actual pressure in the high side, It only disables the compressor if it is over 420 psi. The wire I fixed is an aftermarket pressure switch which has no data, it is just powering up a relay. Thanks for watching!

[@donaldboyett2571]

I watched the video again, and I see. I ran into one doing the same, but It read no pressure on the high side and wouldn't enable the clutch, and it was the wiring on the transducer. I enjoy the videos and watch them all

[@advancedleveldiagnostics]

@@donaldboyett2571 Thanks! that's good to know! I've seen that on Toyotas a few times, but I don't think I've had one on a Chevy yet.

[@donaldboyett2571]

@advancedleveldiagnostics It was a newer pick up were the pressure transducer is by the compressor

[@kyletuttle9064]

Good find man keep diaging

[@Wuilmer39]

I work on school buses and it’s hard to find diagrams for the aftermarket systems (if they even exist lol) it’s a PITA

[@D-Marq88]

Great diag. In a job like this, are you charging straight time to the customer?

[@advancedleveldiagnostics]

I didn't actually charge the full amount of time, But I reserve the right too. They are a really good customer and I was filming so I didn't charge for all the time.

[@123hooterman]

I have an older 2001 express mini bus. I'm trying to convert back to just dash ac and delete the aux cooling. Would you be open to do a remote consultation. My pressure switch on the accumulator was all custom and had wires running to the overhead compartment. The green control wire on the dash max ac was swapped too.

[@advancedleveldiagnostics]

As you can tell from this video, I'm clearly no expert on busses😄

[@borgsimpson935]

Have 2 say,,,,, awesome tutorial. Asking 4 advice... Do we use, electrical tape??? Or will , Liquid Tape... work for the wire piercing???

[@advancedleveldiagnostics]

I use clear nail polish.

[@borgsimpson935]

I've actually seen novice gearhead Use. Duct tape

[@advancedleveldiagnostics]

@@borgsimpson935 lol, Liquid electric tape works fine. It's just really messy. I use Nail polish, which is a lot neater, I think I learned it from Paul Danner, but I may be mistaken

[@3TsMOBILEMECHANIC]

Ok so how do you like the topdon? And how do you do the screen share like you did with the wiring diagrams? I believe I can use split screen with me autel and see Alldata but don’t know how to make it share like you did. Great find by the way love these types of diagnostics

[@advancedleveldiagnostics]

I really like Topdon, its really a matter of what your used too, if you only used Autel it might take time getting used to it. I always had a Launch Scanner so the software is identical. The screen sharing I use screen recorder on my computer and then edit it together with my regular footage. I'm not sure the screen recording abilities on the Autel but I'm sure you can find an app that will work.

[@NextLevelAutoDiagnosticsLLC]

I felt the frustration (especially working on a hot day) for hours. Awesome work and hope you got paid for all the time u put in. BTW, did the bus company finally gave u the diagrams or elsewhere?

[@advancedleveldiagnostics]

When I was finished they emailed me three diagrams, I was so done with this bus, that I didn't even check if they would of helped😂

[@NextLevelAutoDiagnosticsLLC]

​@@advancedleveldiagnostics oh ok.....very nice

[@sheerwillsurvival2064]

Can you do both can high and low on this at one time on this DSO I am thinking of buying it

[@advancedleveldiagnostics]

Yes no problem

[@sheerwillsurvival2064]

@@advancedleveldiagnostics thanks going to get one

[@sheerwillsurvival2064]

Do those adapters come with that DSO for banana jacks or did you get elsewhere??

[@advancedleveldiagnostics]

No, that lead is a Pico lead. its a standard BNC connector

[@sheerwillsurvival2064]

@@advancedleveldiagnostics 👍🏻

[@zoharhagbi6685]

❤

[@Max-j2r]

❤❤❤❤❤

[@CoryMcDermott]

With it being 90+ degrees outside this week in Ohio…..I now understand why you wear a white shirt 😅

[@advancedleveldiagnostics]

It's in the 90's hear as well

[@IO-zz2xy]

Sound is very bad. Sounds like you have automatic volume control on

[@commenter5469]

That manifold looks like TiF clone.

[@advancedleveldiagnostics]

I'm not familiar with Tif; these are made by Master Cool.

[@sheerwillsurvival2064]

Lol short bus . So many jokes 😁

[@lupedelacruz4152]

Wow great find amigo 👍 love your videos thanks for sharing

[@joeandgod1]

Some shops that call me to do a diagnosis, don't have wiring diagrams and I'm thinking, what the hell are y'all doing. These are some old school shops.

[@advancedleveldiagnostics]

Same here, I can't understand it.

[@Wayne-p7n]

Diagrams? we dont need no stinking diagrams

[@michaelpatton5012]

I'm happy i luck up on your videos. You don't mess around. That brand of scanner you uses. is it better than Autel

[@advancedleveldiagnostics]

I wouldn't say it's better than autel, it's a launch based scan tool I they are equal to autel. Each one has there advantages. I personally prefer TopDon to autel. That's probably because of what I'm used to.