[aj88cab]

There are a couple items being discussed that possibly need clarification.

The original reed switch jumper mod was accomplished with a jumper wire across the reed switch circuit. This completed the control circuit for the FW relay coil and ran the FW blowers. The problem was that this control circuit power is always hot and independent of the levers or any switch. The result was that the FW blowers ran whenever the engine was on, even when the heater levers were down (OFF). The modified mod, uses the power from the engine blower circuit to operate the FW relay coil so the FW blowers only turn on when the engine blower is turned on. Some discussions have indicated that this is only applicable to "later" relays, but I am not sure that is correct. I believe the "always hot" reed switch control power is the same for all models.

The question of the FW blowers running on the "0" setting if the heater levers are up (ON) is not an issue, is it designed that way. There are a couple of reason for this I believe. One is that there is too much heat running through the system to not have the FW blower fan "moving air" when the heater levers are ON. And also, the FW fans are "in-line" and block the flow of hot air if they are not running. So the "0" & "1" setting are designed to run at the same (slow) speed whenever the heater levers are up (even just a little).