Engine Speed Signal

Engine Speed Signal

The Air Conditioning Control Module (A/CCM) receives an engine speed signal from the Engine Control Module (ECM).

This signal facilitates compressor lock sensing (12 cyl. vehicles only).

This signal also aids the A/CCM inhibition of the heated screen relays. At engine speeds lower than 800 RPM the A/CCM assumes poor idle or engine not running and will not permit the selection of the heated screens.