JD 330 GLOW PLUG LIGHT STAYS ON

david0621 · Aug 16, 2020

My JD 330 glow plug light stays lit after starting, but is about half as bright. The problem began after the battery terminal connection corroded and was arcing. After I reattached the battery cable, the problem with the light staying on began. Any help with this is genuinely appreciated!

Roadworthy · Aug 16, 2020

You need to start troubleshooting to see what is really happening. If the light is on put a voltmeter on a glow plug and see if it's getting power. It is not good to run glow plugs all the time - they burn out. Find out of that model has a glow plug relay - it may be sticking. Perhaps it is only lighting the indicator light. It is also very possible you have a high resistance leak to ground. Thoroughly clean both battery posts, the connectors on the battery. Be sure the frame ground is clean and secure. That may solve the whole problem.

radios1 · Aug 16, 2020

John Deere P/N is AM138537 at ~$75 a pop. is absurd!. TRULY!.. JD does this to make extra money on parts they know are cheap to make, but are expected to make them a windfall when the part does fail!... it's probably just a delay relay made up to look like something complicated, but it's not!.. there should be a page on the internet showing how to bypass this, and make it manually controlled!..

Roadworthy · Aug 16, 2020

Many older tractors lacked a glow plug controller. You manually activated the circuit which ran through a nichrome dropping resistor. The plugs would get their 10.5 volts while the resistor dropped about 1.5 volts and glowed red to show it was working. Of course it only glowed dimly and you could barely see it if you could see the thing at all but it did the job. It would be a simple matter to convert to that type control.

david0621 · Aug 16, 2020

Thanks Roadworthy! Great advice. I cleaned the battery terminals and checked the glow plug voltage. It went down to 0 after the warm up. The glow plug light stays on, but at least I know it is not powering the plugs, so is safe to use. The glow plug light goes dimmer after a few seconds but remains lighted.

david0621 · Aug 16, 2020

Thanks K7LN! I will try reseating the plug on the relay. Thank you for your help!

david0621 · Aug 16, 2020

Thanks Radios1! I will check that out and see if I can hook up a switch to shut it off after the engine is running. I love Long Island and trained at the Steinway factory as a piano tech. Have made many trips there over the years and was there about a year ago. I hope you are doing okay during all of this craziness! Best wishes!

Kish318420 · Aug 16, 2020

Check the grounds, there might be one in the pedestal for the dash cluster lights that has corrosion. It still looks like the relay has an internal short causing your problem (look at far right in the wiring diagram for lamp/relay/glow plugs/ fuel pump). If short get bad enough fuel pump could be effected, center on the other two diagrams for the 332View attachment John_Deere 330 LG TM1591 (071595) Schematic.pdf View attachment John_Deere 332 LG TM1591 (-475000) (071595).pdf View attachment John_Deere 332 LG TM1591 (475001-)(071595).pdf