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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[@sohailrabani]

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

[@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!

[@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!

[@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!

[@Nemesis-yn5wv]

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

[@mikedavidson2117]

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

[@bartscave]

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

[@advancedleveldiagnostics]

Thanks!

[@jmanatee]

Crazy what aftermarket stuff does to a diag

[@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!

[@djosbun]

Excellent work, Lazer! 👍🏼

[@advancedleveldiagnostics]

Thanks!

[@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!

[@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!

[@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]

💯

[@NoName-yr1jv]

Well done 👍

[@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!

[@bobbywarthan5173]

Once again i love you thought process when diaging vehicles

[@advancedleveldiagnostics]

Thanks!

[@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

[@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

[@kyletuttle9064]

Good find man keep diaging

[@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

[@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

[@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

[@3TsMOBILEAUTOMOTIVEREPAIR]

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.

[@NextLevelAutoDiagnostics]

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😂

[@NextLevelAutoDiagnostics]

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

[@commenter5469]

That manifold looks like TiF clone.

[@advancedleveldiagnostics]

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

[@CarCraftSignature]

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.

[@zoharhagbi6685]

❤

[@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

[@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

[@manoramachandran9192]

❤❤❤❤❤

[@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 👍🏻

[@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

[@IO-zz2xy]

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

[@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.

[@sheerwillsurvival2064]

Lol short bus . So many jokes 😁

[@lupedelacruz4152]

Wow great find amigo 👍 love your videos thanks for sharing