heat chamber is isolated from the air switching valve top assembly. The bi metal spring is heated by the engine heat. I know because I tested it. the factory manual states that even if the heater element fails, the engine temp should close the Aux Air valve and my test confirmed that to be true. I sealed the heat element chamber to limit the air volume exchange thus slowing the corrosion of teh heat element. The heater is powered by 12 VDC from relay board via fuel pump relay's positive
Rod: the screw is an adjustment. I recomend putting it back to hwere it was unless you are going to cycle the valve to test it prior to re-sealing it . I think idle hunting is indicative of lean idle adjust on top pot on teh ECU. check Brads site under component failure analysis
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