Hi guys,
FIL's 7260 has a bad ThermoUnit (I think) that is the input to the glow plug controller. It's the one on the thermostat housing with a short pigtail lead, Cub calls it p/n MA-31A90-02100. The plugs stay on most of the time unless I unplug the lead.
Next to it on the thermostat housing is the ThermoSwitch (I think) that has a male spade connector and is the input for the TEMP gauge. Cub calls it p/n MA-MD001380.
I'm intending to pull them both out and test them in a hot water or oil bath, but the Cub Service Manual is very confusing regarding the correct test resistances, especially for the ThermoSwitch, and I'm confused as to which is which. The manual for the ThermoUNIT has variable resistance of 80ohms @ 50c, 29.5ohms @ 80c, 10ohms @ 120c. This sounds to me like what a temp gauge would need, right?
The manual says that the ThermoSWITCH resistance should be 30mohms @ 120c and the temperature at which the switch turns ON should be 111c. This sounds like an appropriate input for the glow plug controller, but ON (presumably about zero ohms) at 111c and then 30mohms at 120c makes no sense. I'm reading the 30m ohms as 30 MEG-ohms. Perhaps they mean 30 milli-ohms?
Has anyone run into this before and have it sorted out?
Do I have the functions of the devices reversed? Is the UNIT for the gauge and the SWITCH for the glowplugs? If so, a previous owner has reversed the wiring!
- Jay
FIL's 7260 has a bad ThermoUnit (I think) that is the input to the glow plug controller. It's the one on the thermostat housing with a short pigtail lead, Cub calls it p/n MA-31A90-02100. The plugs stay on most of the time unless I unplug the lead.
Next to it on the thermostat housing is the ThermoSwitch (I think) that has a male spade connector and is the input for the TEMP gauge. Cub calls it p/n MA-MD001380.
I'm intending to pull them both out and test them in a hot water or oil bath, but the Cub Service Manual is very confusing regarding the correct test resistances, especially for the ThermoSwitch, and I'm confused as to which is which. The manual for the ThermoUNIT has variable resistance of 80ohms @ 50c, 29.5ohms @ 80c, 10ohms @ 120c. This sounds to me like what a temp gauge would need, right?
The manual says that the ThermoSWITCH resistance should be 30mohms @ 120c and the temperature at which the switch turns ON should be 111c. This sounds like an appropriate input for the glow plug controller, but ON (presumably about zero ohms) at 111c and then 30mohms at 120c makes no sense. I'm reading the 30m ohms as 30 MEG-ohms. Perhaps they mean 30 milli-ohms?
Has anyone run into this before and have it sorted out?
Do I have the functions of the devices reversed? Is the UNIT for the gauge and the SWITCH for the glowplugs? If so, a previous owner has reversed the wiring!
- Jay
