Glow Plug Operation IH 434

sixbales · Dec 4, 2016

Howdy,

On the wiring diagram for a IH 434, there are two wires from the key switch to the resistor indicator. One to the input side of the resistor indicator from terminal 3 of the switch, and the other on glow plug side (can't read the switch terminal number). It appears to me that the second wire/switch position bypasses the resistor. My GUESS is that the resistor is bypassed when the switch is in the crank position. Can anyone shed some light on this?? Thanks.

Rex in Australia · Dec 5, 2016

Pretty sure that the other terminal just provides power to the glow plugs when the engine is cranking.
It wouldn't bypass the indicator as that is simply another "glow plug" in the circuit. (Same resistance as the glow plugs) and Shows when they are hot.
People will probably chime in bagging the system. But if everything is set up properly it works fine. My 434 is 1969 model. STILL on original glow plugs and starts and runs perfectly.
Rx

JDEM · Dec 5, 2016

Indicator has the same resistance a a glow-plug and must be kept in series with the plugs for all to work correctly. In essence, you have five plugs in series when making heat and voltage drops to 9/10th of a volt at each plug.

Glow Plug Operation IH 434

sixbales

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Rex in Australia

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JDEM

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