I’ve mentioned the Automatic Heat option several times so I guess a little background on this option is in order.
Few people are aware that Buick engineers cleverly designed the world’s first climate control system for their 1959 vehicles. “Automatic Heat” was an extremely rare option that was available on all models and could even be combined with Air Conditioning. This intricate system was not shared with any other GM Division (not even Cadillac) and was a one-year only option. Cars equipped with this unique feature are easily identified by the prominent “Heater Thermostat” wording displayed in a reddish orange color on the right side instrument panel pod (see previous post).
Automatic Heat functioned similar to modern day climate control, only it was accomplished without modern electronics. Because the system was designed to be entirely automatic, cars with this option do not have a manual blower switch. The idea was to set the dash mounted thermostat control lever to a position that provided a comfortable cabin temperature and let the system do the rest. The feature was so sophisticated that it prevented the blower from allowing cold air to enter the cabin.
The system utilized a complex network of electric water and air thermo switches combined with multiple vacuum diaphragms and tubing. The water thermo switch was installed directly into one heater hose in the engine bay and it monitored water temperature. Two air thermo switches were required, one detected inside air temperature and the other outside air temperature.
Upon starting the car the system was automatically energized and the water thermo switch would monitor water temperature until it hit approximately 100 degrees F. If the outside air thermo switch detected a temperature below the operator’s system setting, it would work in tandem with the water thermo switch to complete the circuit and automatically turn the blower on at low speed (this sequence prevented the blower from operating before the heater core was warm thereby preventing cold air from blowing into the cabin). Once the water temperature reached approximately 120 degrees F, the water thermo switch automatically increased blower speed to high. When the interior temperature reached approximately 73 degrees F (or whatever temperature the operator selected), the inside air thermo switch lowered the blower speed back down to low. Unique integration components were added to the system for cars equipped with both the Automatic Heat and Air Conditioning options.
The heating/cooling system was so complex that the 1959 Chassis Service Manual contains six pages of diagrams detailing the multitude of different positions of the four vacuum diaphragms and how they direct airflow based on the dash control settings. One interesting fact is that the 1959 Buick Owners Manual states, “On cars equipped with both air conditioning and heating, both units may be operated simultaneously; the air conditioning providing cool air for upper level while the heating system warms lower level.”
The system was not without its problems, the April 20, 1959 Buick Special Service Information Bulletin discusses an issue concerning the Automatic Heater option. The bulletin references a new Automatic Heater Blower Control package to help refine system operation. The package included a newly designed Ranco heater valve that was much more sensitive, a new thermal switch design, new resistor, and all the necessary wiring. The new kit provided for three automatic blower speeds instead of two. With Low, Medium, and High speeds newly available, the kit allowed for more effective air temperature control and alleviated customer complaints of blower noise and excessive air outlet temperatures. Low and Medium speeds were used above 25 degrees F, and high was engaged below 25 degrees F.
All things considered, Automatic Heat was years ahead of its time and remains one of the most rare and unique options ever installed on a production Buick. When properly maintained the system was known to provide years of trouble free service with reports of some 1959 Buicks still operating with the system performing flawlessly after 50 years…a true testament to Buick engineering!
Below is how the 1959 Buick Automatic Heat option system is described in the actual 1959 Buick Facts Book (Click on Picture to Enlarge).
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~ Tom Sidoti
1959 Buick Electra 225 Convertible