[margozzi]

Hello everyone, I am offering repair services for ATC (Automatic Temperature Control) units on mid 60's to 70's Pontiac's. I spent the time to figure out how the entire system works and can get your ATC module working as is should. I also test the entire functionality of the ATC's vacuum switch, control over the fan, calibrate the temp sensor inputs, etc.

I live near San Jose CA, so you will need to ship the unit to me.

The cost depends on whats wrong with it, however a baseline charge is ~ $200 + shipping out and back.

Please contact me if you have questions, I'm also happy to help you debug the ATC system before you pull the module and ship it.

Thank You!

Paul Margozzi
(408) 888-4374

[stevep]

Can you repair the power servo on mid 60's cars?

[margozzi]

Steve, can you send a picture of the power servo, thanks, Paul

[Mark66]

Paul:

You must be one of less than a handful of people who has taken the time to fully understand the workings of GM’s 60's and 70"s ATC systems. I for one am glad you did!

I have a 1966 Pontiac Bonneville Brougham that has an ATC system – currently inoperable. It is interesting to note that the DAFT Tool 1972 “Automatic Temperature Control Service Manual” did not include the 1965-1970 Pontiac ATC system. With reference to these particular years of Pontiac ATC’s, the DAFT books says “Total production of these [Pontiac] systems did not exceed 2% of the cars built in any one model year. Because of the small number of cars involved, descriptions and servicing of these systems has been omitted”. So it seems that 1965 to 1970 big Pontiac buyers did not see value in upgrading from the Custom Air Conditioner option (in 1966 a base price of $421.28) to the Automatic Temperature Control Air Conditioning option (in 1966 a further additional base cost of $63.19).
I have found, at least for 1966, the Pontiac Air Conditioning Shop Manual and Pontiac Craftsman News provide quite a bit of useful support information. And Pontiac also published a stand-along “Pontiac Automatic Temperature Control – 1965-1966 – Servicing and Repairing, Model with Auto Temp” manual. And there is probably some training literature of which I am not aware.

And there are a couple of diagnostic testers that were released (after 1966) that can, it appears, be used to help identify problems with the 1966 Pontiac ATC system (and later GM - and non GM - ATC systems). These include the Robinair/Kent Moore J-23678 “Electro-Vacuum Programmer – Automatic Temperature Control Tester” and the surprisingly sophisticated looking “GM Programmer Bench Test Universal Analyzer II for Automatic Temperature Control Systems”. The GM Programmer does not seem to have a Kent Moore number and may have been developed and released directly by GM. These two units are readily available on Ebay – a 3rd test unit, Kent Moore J-22684 (Automatic Temperature Control Tester), released in 1967 for, it seems, only Pontiacs, is more difficult to find.
One headache I am running into is locating - and fixing - the various vacuum links in the many, many hoses that are used in this unit – what a pain. Crawling under the dash to de-bug vacuum leaks is for the young and thin only. For instance, It would seem take a Wallenda family member to connect the vacuum multi-hose coupler to the ATC control unit while in the car.

So I applaud your efforts to understand and repair these systems. You may see some of my components in the future.

[margozzi]

Mark,

Thank you so much I appreciate the kind words. Yeah, I put in a crazy amount of time figuring out the entire system, not just the ATC programmer (module)... but I had fun and I hope that I can help anyone with a limping ATC. If you are interested please let me know, I'd love to get your system going again. I did come across (and now own) a Robin Air test system, but I have to say its rather crude in what it can test for. I have also developed a document that can be used to debug the system and shows exactly how the module works and how to fix it.

Thank you for reaching out to me, if you would be so kind as to send a pic of the 66 ATC that would be great. The picture of the ATC I'm most familiar with was pictured in my ad... maybe the 66 is the same?

Thanks so much,
Paul

[Goatracer1]

I worked for a Pontiac dealer back in the day. We had a used 1975(?) Grand Prix with ATC that we couldn't fix after weeks working on it. It was finally sent to the local Caddy dealer hoping their experience would allow them to fix it. After 6 weeks they sent it back to us. They said that they couldn't fix it either but they did bill us for their time trying.

[margozzi]

Mark,

I also wanted to thank you for the historical info on the production numbers for the ATC, I always wondered about that. I assumed it was low, but after having fixed a bunch of these it seems that they are everywhere ;-) Even at 2% of the 1969 GP production that's over 2000 ATC's. I was not aware of the “Pontiac Automatic Temperature Control – 1965-1966 – Servicing and Repairing, Model with Auto Temp” manual you noted...I'll have to see if I can find that.

I'm not surprised that the Caddy dealer gave up and billed your dealership anyway for the 75 GP ATC. If you have an ATC car its hard to not fix it because it controls everything for the ventilation system. And, depending on what position it decides to stop working the heat could be on wide open or some other random setting that you may not want at any point in time. I see people just disconect the arm and push the door one way or the other, but you still have no control over the vents or the fan.

If you are inclined get a hold of me and we can check the ATC out... I know what you mean about the vacuum lines, there are a lot of them, luckily they are usually ok, the double sided pods are what usually give out, the singles are fine since they don't have the rolling grommet that gives out.

Enjoy your Bonneville Brougham.

Attached is a pic of my 69 GP with ATC.

Thanks, Paul

[Mark66]

:Paul:

Send me a PM with your email address and I will send you a PDF of the ATC manual. It only applies to 1965 and 1966 big Pontiacs but should interest you.

From a diagnostic perspective the 1965 and 1966 Pontiac ATC units are virtually identical although changes were made mid year in 1965 to some ATC components and many part numbers between the two years are not the same (although they look identical). 1965 big Pontiacs also had an ATC temperature sensor in the instrument panel dash pad while 1966 big Pontiacs had it under (and not part of) the dash pad.

Always interesting trying to debug older technology.

Mark