New Holland 1715 glow plugs not working

[sdsherer]

Not getting power to glow plugs. Also, dash glow plug indicator coil does not glow at all, so obviously no power. From the wiring diagram, it appears that both the glow plugs and the glow plug indicator are coming straight off the ignition switch. Is it safe to assume the problem is the ignition switch itself? All fuses seem to be OK (found 3 - 2 5A, and 1 15A.) Starter works fine, so ignition switch must be getting power.

Thinking it's the switch. Ordered a new one. Any other thoughts?

Thanks.

Steve

 

[sdsherer]

Also, while I have your undivided attention, can you tell me what these relays or flashers, or whatever these boxes are (besides the fuses)? Thanks again.

 

[Steve in OH]

Not to back up, but are you certain the problem is not just with the timer? Try leaving the tractor in gear (so it will not crank), and turn the key, to engage the starter… Does the glow plugs indicator light light up?

 

[Roadworthy]

See if you're glow plug indicator is getting power in, then see if it's getting power out. Many older tractor used it as a dropping resistor to lower the battery voltage to the 10.5 volts required by the glow plugs. The nichrome wire tends to corrode at the terminals. These ends can be cleaned. Of course if the wire is burned in the middle the unit needs replaced.

 

[TractorTech]

See if you're glow plug indicator is getting power in, then see if it's getting power out. Many older tractor used it as a dropping resistor to lower the battery voltage to the 10.5 volts required by the glow plugs. The nichrome wire tends to corrode at the terminals. These ends can be cleaned. Of course if the wire is burned in the middle the unit needs replaced.

Right, I had the wrong description (deleted post) for a 1715. The relays are flasher and safety (neutral start) relays. No timer.
It does have the old style glow plug circuit and is very straight forward. Ignition to glow plug coil to glow plugs.

 

[Roadworthy]

If you need a new indicator / dropping resistor I purchased one awhile back on eBay. My biggest problem was finding one for a four cylinder tractor. It seems most diesels are three cylinder.

 

[sdsherer]

So, I got the 1715 working yesterday and I got lucky because it did turn out that putting a new switch in caused things to work. Thanks for all the useful suggestions.

 

[Armindo86]

It sounds like you’ve made significant progress in troubleshooting the ignition issue. Before you proceed with replacing the ignition switch, there are several critical steps to consider. Firstly, verify that power is reaching the ignition switch by using a multimeter to check for voltage at its terminals when the key is in the "ON" position. Next, inspect the wiring and connectors between the ignition switch and the glow plugs, along with the glow plug indicator, looking for any signs of damage, corrosion, or loose connections that could disrupt power flow.

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Additionally, check if there is a glow plug relay in the circuit; a malfunctioning relay can prevent power from reaching the glow plugs. It's also important to ensure that all ground connections related to the glow plugs and ignition switch are secure, as poor grounding can lead to similar issues. If possible, test the glow plugs themselves, as a shorted or open plug can affect the entire circuit. Lastly, even if all fuses appear to be intact, double-check those associated with the glow plug system for any hidden cracks. If, after following these steps, the new ignition switch does not resolve the problem, consider consulting your vehicle’s service manual for further troubleshooting guidance or wiring diagrams specific to your model. Good luck!