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diagnostic tools

coley13 on Tue September 18, 2007 8:28 PM User is offline

let me introduce myself, my names Craig and i live in Australia. i just stumbled across this site and so far i'm mighty impressed. i'm a former A/C mechanic who has been out of the industry for many years. I'm looking at getting back into the industry and starting my own mobile A/C service and accessories business.

i've been looking at different service and diagnostic equipment. i apologise if this topic has come up before but i was looking at the Bright Solutions a/c investigator. My question is this diagnostic tool any good or will it give me a wide variety of possible causes of failure that i already would know or does it pin point certain failures pretty well to the exact problem. it's been 10 years now and i mostly worked with R12 and used old school methods of diagnosis. i realise theres been alot of changes in the industry and i would like to get with the times and technology.

cheers craig

bohica2xo on Wed September 19, 2007 1:39 PM User is offline

Welcome to the forum Craig

We have a couple of centuries of combined knowledge here, and it is all searchable. Glad to have ya.

Not much has changed in the refrigerant loop since you last looked at a system - most of the changes are control related. I can think of better places to spend 2,000 USD than the Bright Investigator.

If you work on newer cars, you need a good code reader, and a subscription to Mitchell or the like. The on-board computer(s) already can provide plenty of A/C data in most cases. Many ATC systems will do more diagnostic work than the bright unit while the customer drives the car...

We have a whole generation of kids "working" on A/C systems with a machine that will evac & charge all on it's own. They have no real knowledge of how (or why) a system works, and a simple poor connection will have them replacing parts over & over. A high side connector that does not depress a schrader valve gives a gauge reading of "zero". The untrained kid with the machine reads the chart, and says with authority "your compressor is shot, it needs to be replaced". I watched someone put 3 compressors on, blaming the rebuilder each time...

If you have the skills to actually troubleshoot a system, you are way ahead of the curve. I would go through my gauge set and replace the seals & hoses. You will need 134a connectors (if they use them is OZ). In addition I would add the following to my test equipment toolbox:

1) A code reader or scanner. Don't go overboard, it just needs to read the codes.

2) A thermocouple thermometer, and several thermocouples. A 2 channel unit will cost you about 100 usd for a reliable tool. Thermocouples (T/C's) last forever if you do not abuse them. A bit of insulation & a cable tie will give you accurate temp data. I would not use an infrared or laser thermometer if it was free.

3) A good DVM, and inductive DC current clamp. Many times with solid state controls we lose track of the importance of current as well as voltage. A common thread is "voltage at the clutch connector" but no engagement. A measurement under load will show almost no current flowing...

On the hard tooling side I would have the necessary tools for clutch removal, springlock tools, etc.

One of the things I noticed in the Bright manual, is a wire piercing probe. This is one of my pet peeves in the automotive test world. Puncturing the insulation to test a wire leave a place for corrosion to start - and not one you will usually look for. If you need to get into a circuit, pull the plug. If you find a load test that requires a connected plug, make or buy a proper test adaptor.

Spend some time on the site, we have a lot of fun.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

TRB on Wed September 19, 2007 1:46 PM User is offlineView users profile

I agree with bohica2xo. It's still the same game as 20 years ago. Just a few changes do to R134a.

If I were to invest that kind of money I would get a scanner that I could use for more than just a/c.

Our friends at BATAuto have some scanners to check out.


When considering your next auto A/C purchase, please consider the site that supports you:

NickD on Thu September 20, 2007 11:14 AM User is offline

Ha, nice to learn there is a somebody else from Australia besides graeme, perhaps we can get a more balanced view of your country. Welcome! We are not the best on HC refrigerants and kind of stick with what our laws tell us to use, whether we like it or not, most of us do not like blends where two gases are mixed together and will separate if left alone. We can still use R-12, just takes a bit of spare cash is all, retrofitting is kind of dying off as most R-12 vehicles are now beyond their average life. The vast number of retrofitting posts has drastically quieted down over the last five years. Those you see here are mostly antique vehicle restorations, and I for one don't care to see a car listed as an antique when it seems like yesterday they were on the new car showroom floors.

Scanners or readers are a curse inflicted on us since OBDII in the 1996 model year, practically all vehicles before then had means of reading codes even though it meant counting check engine lamp flashes to learn why that dang check engine lamp came on. OBDII was originally intended to unify all those codes with one simple reader which a far more accurate word than a scanner, all the information is there in the computer, just have to be able to read it with these way overpriced devices. And more money is spent on encrypting and serializing these codes than putting a cheap LCD display on the dash so a guy wouldn't have to invest half of his yearly gross income. Basic scanners are just that, basic, only showing a few codes, each OE went his own way with all these accessories that require additional software to interpret peculiar to each car make, so it becomes an expensive proposition.

AC systems are basic as well, and really haven't changed that much in the last hundred years, what has changed is that there is a thousand different ways of doing exactly the same thing, so circuit diagrams are a must. Equally important is component location information. While an average vehicle is only less than six feet wide, sixteen feet long, and less than five feet high, there are just all kinds of places to hide that sensor that you can spend days trying to find.

While you use to be able to work on an MVAC system wearing your Sunday suit and maybe only getting your finger tips dirty, need a lift today as they found new places to put this stuff. And yes, the evaporator is the first component starting off on the production line with the entire rest of the vehicle wrapped around it.

While Henry Ford I provided a simple tool kit where a guy could do 95% of the work on his car, today you need a specialized tool for just about any task. They have more ways to remove a simple hub than Carter has liver pills. And they keep on changing that!

For diagnostics, still use my nose, ears, eyes, and feel as the key elements to let me know quickly what's going on. Still rely on manifold gauges, but they also had to go downhill on R-134a ports to make sure they would leak. Compressor seals is just about as far as a guy can go for repairing a compressor as well as the pulley bearing. The rest you need a compressor factory for, but any single replacement part cost at least twice as much as a new compressor, so not very profitable to go any further than the seal. And they did discover how to make seals leak along with R-134a ports. So you will find things to keep you busy.

coley13 on Thu September 20, 2007 8:31 PM User is offline

thanks for the replies, i'll definately look into a scanner. OBDII has only just become mandatory in australia recently with manufactures so i have to do a little research on OBDI and OBDII combination scanners to suit our market.

R12 is pretty well none existant these days here aswell. i had worked on 134a systems for a short while around "1995" before i left the game. i'll just chase up some pressure/temp charts to suit 134a and go from there.
cheers craig

NickD on Fri September 21, 2007 9:11 AM User is offline

The more popular handheld 3rd party scanners are the Actron CP9150 or the Auto Xray EZ-Scan, another alternative is to purchase the interfacing leads and programs for a notebook computer that offer addition software for those specialized items, but then you have the inconvenience of hauling a notebook around.

To my knowledge, no 3rd party scanner covers ABS or air bag codes, they don't want the liability. But I believe that Snap-On and OTC scanners have the software, but are very pricey units. To the best of my knowledge, reflashing ram is limited to the dealers and reflashing may be necessary if you just have to change a component as each has it's own unique ident code. This not only requires a dedicated scanner like the GM Tech II that costs around $5,600.00, but a notebook as well with access to the GM network to download the latest software. Ford had a dedicated computer for this at first, it cost the dealers, $44,000.00, but later, reduced that price for the dealers to under $6,000.00. Haven't seen what Mercedes or BMW is using, but also heard it was extremely expensive.

Seems a crime since with a cheap home computer, can download all you need for free on the internet to reflash your ram. All I can say, is if you run into something like this, make friends with your local dealers

Ironically, we were always taught our competition is our enemy, starting with school sports and into the corporate world when the exact opposite is true, we are in the same boat together. If a local dealer does not have a good AC man, be their good AC man with special rates, so they can make a couple of bucks and in turn, keep you busy, if you have flashing problems, they are there for you.

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