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  • Mike Rosenberg

Automatic Temperature Control (ATC) - the newest innovation

Updated: May 18, 2020

Introduced during the 1967 production year, ATC was a revolutionary design that featured a temperature adjustment wheel. Instead of manually selecting heat, air conditioning or vent, the driver simply selected the desired temperature and the ATC did the rest. Unfortunately, these systems were extremely complex and required a network of vacuum hoses in order to operate. Chrysler technicians were provided with a special testing device to perform system diagnostics and troubleshooting. Of course they needed a Technician reference book to provide instructions on how to use this testing device, named a C-4064 Chrysler Auto Temp Tester. See Ref Book 68-4 and C-4064 Tester below. I was able to locate a mint condition tester on eBay. I have never seen one of these testers before or since.

The "brains" of the ATC system is called the "ATC control unit", located in the front passenger kick panel. When we opened our unit we noticed that it was serviced in 1967 when the car showed 5549 miles.

As is common with ATC control units and 50 year old plastic, the vacuum hose fittings had completely broken off. Using the ATC schematic each vacuum hose was traced back to its source and labled before being reattached to its external hose counterpart. See broken off hose fittings stuck in the hoses in the 1st pic below and the broken off connector tabs in the 2nd pic.

See the disconnected labeled vacuum hoses below. New connectors were added to the ends of each of the vacuum hoses to replace the ones broken off in the control unit. We bypassed the ATC control unit connection hub when reconnecting all of the hoses to the system.. There are around 10 hoses!

See the inside of the ATC control unit below.

See the "good end" of the vacuum hose connector juncture below. Notice that each vacuum hose has a numerical label.....lucky for us.

It was also necessary to replace the "push button" ATC unit in the dashboard. Again, 50 year old plastic doesn't hold up well. See pics of the disassembled dash.

After replacing ATC components and repairing vacuum hose connections, the dash was reinstalled. See pic below.

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