Can a bad ignition switch cause glow plugs not to come ON?

LazyBoy · Nov 10, 2018

For awhile now on my B21 I would sometimes have to cycle the ignition switch ON/Off and back to the glow plug position several times to get the glow plug light to come ON, now it won't come ON at all leading to long starting times, do you think the key switch has gone bad???

countryguy1225 · Nov 10, 2018

My answer is that it's possible, and pretty easy to check. Do you have the wiring print? I recently swapped my ignition due to proven bad contacting for START condition, and then we had someone else tear into their B. for some other things, but his ignition was the same as my L. The simple way to prove or disprove is to check. You just need to remove the cowling to get into the dash/switch. Disconnect the plug, Run the ohm meter across the HOT center lead and the ignition heater terminal. It'll be the wire that goes over to 1 side of the glow heater indicator (does on mine anyway). Do you know how to use an Ohm meter or continuity tester.
-OR
if you can get to the the heater element, See if you get 12V from the wire terminal to ground. Check each side while you turn the key.

the wiring diagram will show if you have a fuse in the system somplace as well.

3Ts · Nov 10, 2018

I have a similar problem. When I turn the key switch to heat the glow plugs nothing happens most of the time. I replaced the key switch and nothing is different. I even bypassed some of the safety switches just to see it those were bad. Nope. Finally traced it to the connector on the new key switch that plugs into the rest of the wiring. It appears that one of the pins is not making good contact. I've tried contact cleaner and a mild abrasive, but that hasn't helped. Next step is to bend the pin a little to see if I can get better contact. I can get the lights to come on by wiggling the connector halves.

countryguy1225 · Nov 11, 2018

On my L2550.. there is no Dash light for this. I look down into the indicator on the ignition cowling and see the wire glow from the hole and it take a few mins to get red. Same with my older Mitsubishi.... Are you saying that you have a regular dash type light-up indicator? if so, then the wiring print should help iron it all out. Pins and connectors are often press-crimped w/ no solder. The wires and the connector often corrode and get wonky. Sounds like you have it nailed down. you may want to see about replacing the pin and recrimping. most pins, plugs, and connectors can be found online at DigiKey.com