Auto A/C Terms - Glossary
Evaporator Temperature Regulator Valve - ETR Valve

Depending on the A/C system design, the evaporator pressure or temperature can be controlled in a variety of ways. On early model Chrysler Corporation A/C systems, an ETR valve was used to maintain the proper evaporator pressures.

The ETR valve was located in the rear suction port of the Chrysler RV-2 A/C compressor. The temperature regulator was later replaced by the pressure regulator valve or EPR valve.

New A/C system designs have eliminated the need for these valves as they have been replaced with cycling clutch systems and pressure sensing switches that cycle the compressor.