When the heater valve is closed the bypass valve diverts the coolant flow back to the engine. The valve maintains coolant flow through the thermostat housing to ensure correct operation of the thermostat.
Brake Master Cyl Reservoir ACDelco GM OE/GM Genuine Parts 84873081
NOS ACDelco GM OE/GM Genuine Parts PT1071 - ABS Harness Connector 15305931 USA
Connector/Pigtail(Body Sw & Rly) ACDelco GM OE/GM Genuine Parts D1780C
Door Lock Relay ACDelco GM OE/GM Genuine Parts 19119238
Buzzer Relay ACDelco GM OE/GM Genuine Parts 19303153
GM Genuine Parts Engine Cooling Fan Blade - GM 19435354
