Where does vacuum line for Heater control valve go?
Generally on most 3rd gens of the fuel injected era it’s on the passenger side near the rear of the intake manifold. There is one vacuum line coming off the manifold that goes to a check valve (a black cylinder with one side tapered in a cone shape).
What is a vacuum check valve?
The check valve is designed to suck out air that is trapped in the brake booster without letting additional air enter the cylinder. This part connects the body of the brake booster to the vacuum hose and is a safety solution that still allows the brakes to work – even if the engine is shut off.
Do check valves work in vacuum?
Vacuum check valves work with venturi vacuum pumps and switches to seal and maintain vacuum levels. With cracking pressure rated at less than 1 in. Hg., they allow air flow in one direction only. Valves can be manually operated or automatically controlled by vacuum switch.
Where is the vacuum check valve located?
So, where is the booster check valve located? You’ll find it at the brake booster vacuum inlet, connecting to the vacuum hose from the engine intake manifold.
How to check the temperature of a heater control valve?
Then check the temperature of the hose on the inlet and outlet sides of the heater control valve. The inlet and outlet hoses should be the same temperature. If the inlet side is warmer than the outlet side, the valve isn’t opening or opening fully. Remove the vacuum line from the vacuum motor and check for engine vacuum.
What causes a vacuum to heat always on?
Since a vacuum operated valve defaults to the fully open heat-on position when vacuum isn’t applied, a loss of vacuum is the first thing to suspect in a “heat always on” condition. The loss of vacuum can be caused by a break in a vacuum line or a faulty vacuum switch.
What can cause a heater control valve to fail?
A heater control valve can fail in several ways. Since a vacuum operated valve defaults to the fully open heat-on position when vacuum isn’t applied, a loss of vacuum is the first thing to suspect in a “heat always on” condition. The loss of vacuum can be caused by a break in a vacuum line or a faulty vacuum switch.
How does a heater control valve work in a car?
In some cars, the heat is regulated by a heater control valve that controls the flow of hot engine coolant from the engine to the car’s heater core. On older vehicles, the valve is operated by a cable, while newer vehicles used a vacuum actuator controlled valve. A heater control valve can fail in several ways.