MEFI Fuel Injection
Exhaust Temperature Switch
Switch is Mounted here (drilled and tapped first)
The switch is located in a protected housing in the manifold. The switch is not mounted in the exhaust stream or the cooling water flow. It only “sees” the temperature of the riser elbow metal. In the picture above, the hole for the switch has not been drilled and tapped. It is NOT drilled all the way through into the exhaust stream. The switches can be knocked out of calibration by being hit or the stud being turned. If the stud for the harness connector is turned, even slightly, the switch is no longer any good and must be replaced. These switches are either wired in parallel with the oil pressure switch or they are wired in parallel with themselves on their own separate circuit. There are 2 systems that use these switches. They are usually referred to as the Engine Mounted Horn system and the Remote Mounted Horn system. The Engine Mounted Horn system was used on the models built between 2001 and 2002. In 2003 we switched to the Remote Mounted Horn system. The operation of these 2 systems is discussed on the following pages. Monitored items for both systems are: oil pressure, engine water temperature and exhaust riser temperature.
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