L35 Glow Plug ?

pat331 · Nov 16, 2009

New member here and I really enjoy and appreciate these forums. I have a '98 L35 w/ 890 hrs. that has a glow plug problem. I noticed while mowing after a few hours that the glow plug light was lighted. I checked the glow plug circuit and it was energized everytime the light was on. It appears either the glow plug controller or the glow plug relay is bad. I pulled off the wire that goes to the glow plugs so I could continue to use the tractor.

Is there a way to determine if the relay or controller is bad or could it be something else? Thanks!

pat331 · Nov 23, 2009

I checked all wires terminated on the ignition switch. All are protected with a rubber cover that appear to be in good shape. I did try wiggling each one and they seemed tight. But when I turned the switch on (wire still disconnected from the relay going to the glow plugs) to test whether or not the light stayed on, the light went off as it normally did. I tired it probably 5 or 6 times over an hour. This was last night after I parked the tractor in the shop and after dark. So I hope to test it tonight by driving it around outside for 30 min. or so. I'll post a new report after that.

pat331 · Nov 24, 2009

I checked the wires to the ignition switch before cranking the engine. Still good. Fired up the engine and the glow plug light stayed on (wire from glow plug relay to glow plugs still unplugged). I then used it to move some dirt for 30 minutes and the glow plug light stayed on the entire time. Parked it, killed the engine, and tried the switch again and found the glow plug light still stayed on. I suspect either the relay or the glow plug controller is bad. I also wondered if the temperature sensor in the engine could be causing my problem. Any help in identifying the culprit would be appreciated.

Ob1kubota · Nov 25, 2009

pat331 said:
I checked the wires to the ignition switch before cranking the engine. Still good. Fired up the engine and the glow plug light stayed on (wire from glow plug relay to glow plugs still unplugged). I then used it to move some dirt for 30 minutes and the glow plug light stayed on the entire time. Parked it, killed the engine, and tried the switch again and found the glow plug light still stayed on. I suspect either the relay or the glow plug controller is bad. I also wondered if the temperature sensor in the engine could be causing my problem. Any help in identifying the culprit would be appreciated.

I'm really sticking my neck out here but I bet its the Glow Plug controller and You may want to bypass the relay and timer and make your own set-up to manually use the glow plugs only as needed. I have done this a few times. Use a heavy relay/solenoid (the existing one may work, or a new 80-100 amp rated relay) at least what your battery will flow... a normally off momentary contact switch and wire it to the solenoid/relay. This allows you to control how much time you use the glow plugs and when. I found it works much better than any automated system like on my ZDs... Go l@@k at this site for components... http://order.waytekwire.com/cgi-bin...37+FUNCPARMS+WEBCMP(S0020):01+WEBID(S0020):01

pat331 · Nov 30, 2009

Thanks for the suggestion. I used the tractor over the Thanksgiving Holiday and noticed the glow plug light come on and stayed on one day, then the next, it worked as designed, and yesterday, it worked correctly part of the time and then lighted up on its own as I was operating the tractor. As you well know, glow plugs aren't always needed here in the Ft. Worth area, but would be needed on the few days when the temperature does drop. I couldn't get by like I have been if I lived up North. I'll post a response after I get it fixed. Thanks again.

heydannie · Jun 29, 2010

Maybe a little late for a reply but I had the same problem. Traced it to the 3relays under the console. It is the back one of the 2 side by side. I cleaned the contacts on the relay with sand paper and sprayed contact cleaner on both the contacts and the plug itself. Then with the switch off I took a pair of needle nose pliers and squeesed the spade connectors in the plug so they would make better contact. This seems to have worked so far... Thanks for the directions everyone....Dannie

handyman · Jun 29, 2010

ob1kubota glad to see you jump in I agree with your thought between you and vic it will be figured out. Missed you on site hope you are doing ok. handy

pat331 · Jul 1, 2010

Handy, that was an old post by Ob1 dated 11/25/09. As far as I know, Dec09 was the last time he posted.

On my glow plug problem, I determined the controller was the problem. I'll admit that I didn't clean the contacts as heydannie did and that may clear up my problem. I bypassed the controller by installing a temp. push-button switch to heat up the glow plugs when needed. Here in central Texas, glow plugs are rarely needed. I still intend to purchase a new controller at some point.