torchroadster
Member
My TC29D has a "flaky" ignition switch. By that I mean you have to get turn and push it just right to get it to start. In researching the problem I find that this is not uncommon.
http://www.tractorbynet.com/forums/new-holland-owning-operating/163355-tc29d-ignition-switch-replacement.html
http://www.tractorbynet.com/forums/new-holland-owning-operating/88444-those-starting-problem.html
http://www.tractorbynet.com/forums/new-holland-owning-operating/109372-tc33d-glow-plug-problem-fixed.html
The accepted fix seems to be to replace the NH ignition switch with a more robust part from Napa, PN KS6600
NAPA AUTO PARTS
However this switch does not have a separate position for the glow plug preheat. Others have connected the glow plug circuit to the ACC connection, with the contention that the glow plug timer will limit the glow plugs to only heating while the timer is active.
But when I review the NH schematic for the glow plug control circuit it doesn't seem to work that way.
The glow plug circuit is marked in yellow, the glow plug timer circuit is in blue and the circuit to the indicator lamp is in yelow.
It looks like the glow plug timer ONLY controls the glow plug indicator light on the dash board and the glow plugs are hard wired to the glow plug connection on the ignition switch. Since with the NH switch you have to engage the glow plug heat by pushing in on the switch they can't be accidentally left on. However it seems to me with the NAPA replacement switch the glow plugs would be continuously on when in the ACC position.
Am I missing something? I would like to go with the NAPA switch but if I am interpreting the circuit correctly I don't think this is the best solution. Does anyone know of an aftermarket switch that may have momentary position in addition to ACC, such as the stock New Holland switch that could be substituted?
http://www.tractorbynet.com/forums/new-holland-owning-operating/163355-tc29d-ignition-switch-replacement.html
http://www.tractorbynet.com/forums/new-holland-owning-operating/88444-those-starting-problem.html
http://www.tractorbynet.com/forums/new-holland-owning-operating/109372-tc33d-glow-plug-problem-fixed.html
The accepted fix seems to be to replace the NH ignition switch with a more robust part from Napa, PN KS6600
NAPA AUTO PARTS
However this switch does not have a separate position for the glow plug preheat. Others have connected the glow plug circuit to the ACC connection, with the contention that the glow plug timer will limit the glow plugs to only heating while the timer is active.
"on the TC29D, you actually just turn the key to acc and leave it to heat the plugs. They are on a timer and do not use a spring loaded portion of the switch to activate them. When you turn the key to acc, you can walk away. In about 4 or 5 seconds, you can hear a little "click" which is a relay that turns the plugs back off. The only thing that the spring loaded part of the ignition switch is used for is to start the tractor. I know some tractors may be different but on the TC29, that is how it works. "
But when I review the NH schematic for the glow plug control circuit it doesn't seem to work that way.
The glow plug circuit is marked in yellow, the glow plug timer circuit is in blue and the circuit to the indicator lamp is in yelow.
It looks like the glow plug timer ONLY controls the glow plug indicator light on the dash board and the glow plugs are hard wired to the glow plug connection on the ignition switch. Since with the NH switch you have to engage the glow plug heat by pushing in on the switch they can't be accidentally left on. However it seems to me with the NAPA replacement switch the glow plugs would be continuously on when in the ACC position.
Am I missing something? I would like to go with the NAPA switch but if I am interpreting the circuit correctly I don't think this is the best solution. Does anyone know of an aftermarket switch that may have momentary position in addition to ACC, such as the stock New Holland switch that could be substituted?