By coincidence i had a similar problem this weekend on my TL
First indication was a much faster glowing resistor and a glow moment between off-position and AC position of the key switch.
Then the resistor burnt.
Long story with a lot of stress short:
The black-white wire to the bus grounded itself due to vibrations. This resulted in the burnt resistor but before that a too high current draw through the feed lines to- and the key switch.
I had to replace the main feed connector that fits between dash and the feed line coming from the starter. (burnt also and giving spooky measurements before we found it)
So, with a new keyswitch in place and the resistor bridged (i do have 12V plugs). Tractor was back on the road.
Just as a confirmation:
- Glowplugs have 2 connections to key-switch: 1 pre-heating and 1 starter contact. (both wires being black-red) so yes plugs are heating when starting tractor.
- Currect draw has to be between 15 and 27 Amps dependin on temperature of engine. Cold engine takes 27 amps, hot 15 amps.
a last remark,..
The starting circuit is not fused (starter and glow plugs). The resistor is not a fuse.
IF a cable shorts before the resistor cables will burn quickly.
Therefore my advice to put a battery switch on your main cable and switch off the electrics when parking your tractor.
Melting the connector took 2 seconds and that could have happened during the night or at any given time. The only thing that can stop a fire in that case is disconnecting the battery.
