glow plug indicator

[ric]

Neil, Not yet, ended up doing something else and have not gotten back to this yet. ric

 

[ric]

Fractal, My 245 has always been a little hard to fire as most older L Series tractors tend to be. Although the glow plugs all worked the indicator has never seemed to glow as it should in the time I have owned this tractor. I have a 175 and it's indicator glows as it should. The 175 and 245 are basically the same tractor and are wired the same, but the 245 glow indicator does not work when it should, so I'd like to try to figure out why it doesn't work. Thanks, ric

 

[ric]

Stephen, before I started looking into this I too thought the indicator was in series to reflect how hot the plugs were getting. However, taking this apart revealed two surpises. One the inidcator is not in series and two of the three wires attached to the indicator are hot. This is wired just how it's drawn in the manual but you can't tell which is hot or ground. One wire coming from a pole on the switch is attached to one side of the indicator with the a wire that goes to the glow plugs. Another wire from another pole on the switch is attached to the other side of the indicator. Both wires from the switch are hot when the switch is turned to heat the plugs. The wire from the switch to the indicator and the wire to the glow plugs are in the same wire end connector and are not terminated separately on the indicator meaning if the indicator dropped out of the circuit the plugs would still heat. If this makes any sense you can see why I am curious how this really works. Thanks, ric

 

[Anonymous Poster]

ric,
I just had a look at the wire diagram(I have an old photo copy from my original I loaned to someone once). I think you might be getting fooled by thinking there is power to both sides of the indicator at the same time. Try disconnecting all the wires from the indicator. Then use a test light to check which wire is hot when the switch is turned to the left(preheat), then turn the starter switch to the start position and check the wires. I think the way it is set up is to energize the the glow plugs directly when the starter is engaged bypassing the indicator resistor, so what changes here is the path the current takes depending on the position of the starter switch. Actually you probably could comfim this by just diconnecting the wire which is by itself on the indicator and testing with the light.

 

[ric]

Stephen, When I first disassembled the dash I removed the glow plug indicator to check it for continuity and if the resistance wire was really isolated from the frame as it appeared to be. I then checked continuity of all three wires and the voltage. No problems. Testing with a test light as you suggested. When you turn the switch to heat the plugs both wires from the switch have power. When the switch is in neutral neither are powered. When the switch is turned to start the engine neither wire is powered. During the process I replaced the glow plugs with new ones even though the old ones worked they appeared to work somewhat unevenly when I tested them. I also replaced the glow plug indicator. I checked each component before I installed them to be sure they worked as expected, all checked ok. What seems odd is that both wires to the indicator are hot, hence my curiosity about how this really works. I do have another L Series tractor just like this one, a 175, that is working correctly. I plan to tear it down to see what's different but I just have not done that yet. Hope this helps, thanks, ric.

 

[TonyC]

Sometimes you just gotta chuckle. Here's a thread on glow plug indicators and it has been viewed 563 times with 34 replies. Do we need a life or what! /w3tcompact/icons/smile.gif/w3tcompact/icons/smile.gif/w3tcompact/icons/smile.gif

 

[bky]

thanks ric it helped and i am still looking into the glow prob also

 

[bky]

also ric i hope this pic helps it shows the glow plugs wired in series and the last 1 goes to ground

 

[bky]

i will try pic again

 

[bky]

hey i think i got it down to the right size yeahaw