TC29D glow plugs

[dlctcg]

@Mtsoxfan

I believe the glow plug timer has multiple connection paths... meaning...

When the key is turned to ACC/RUN position the timer should light the dash indicator light & supply ground to the glow plug power relay to energize the glow plugs ONLY for a specified amount of time, deluxe model for 4-5secs & 10-11secs on economy model, & then turn off; this is to keep from burning up the glow plugs when the switch is in the ACC/RUN position or when the tractor is running.

When the Key is turned to the START/CRANK position I believe the circuit is still completed & the glow plugs are still energized as long as you keep the key turned, this is to assist in starting, when the tractor starts & the key returns to the ACC/RUN position then the glow plugs are de-energized.

So if the glow plug timer goes bad I've read multiple different conditions it can cause... yours being one of them. Sometimes the glow plugs will get no voltage at all, ours when it went bad it did the opposite... it kept powering the glow plugs even after the tractor was started... so as your planning to do, testing is definitely your best bet.

I believe for testing you could use any 12volt source as you are just seeing if the timer is working & it is not connected to the tractor, being I had the timer disconnected I just tested it with the tractor battery (disconnected from the tractor) which allowed me to use very short test leads.

 

[Mtsoxfan]

OK, followed directions, light lit, and stayed lit. There is some blinking every couple of seconds.
So, one issue is this timer. Saw online for about $65, so I'll look more today for a cheaper version.
Thanks for all the help.

 

[Mtsoxfan]

Ended up paying 65 for a timer relay. Glow plug light and plugs themselves are now working, thanks to all whe helped me with diagnosis charts.

 

[thclimer]

Ended up paying 65 for a timer relay. Glow plug light and plugs themselves are now working, thanks to all whe helped me with diagnosis charts.

Glad to learn your tractor is back starting and running smoothly and its nice to know what solved the problem!

 

[tmeric7]

When the Key is turned to the START/CRANK position I believe the circuit is still completed & the glow plugs are still energized as long as you keep the key turned

Just to verify, this is definitely true on my TC29DA. I know from reading the wiring diagram and testing voltage at the glow plug busbar.

So there are two ways the timer relay can fail:
1. It can stop working as a timer powering the glow plugs for sever seconds in IGN/RUN
2. It can stop working as a relay powering the glow plugs while cranking

Mine failed in #1, so the tractor cranked for a long time before starting. I purchased a cheaper substitute that worked fine as a timer, but did not perform #2 and would not start the tractor at all. I verified all this with voltage measurements at the glow plug bussbar. I ultimately purchased the expensive dealer part (works correctly) and installed a push button to add some time to the glow plugs if I want. I reported on all this on the New Holland board here:

TC29: how I added glow plug button and sorted out timer relay

My TC29DA has cranked longer to start with the cold, plus some erratic behavior at the glow plug light. This post is to share how I worked though things. I replaced the glow plugs in the process. For documentation, my New Holland P/N is SBA185366190. I paid $30 for eBay replacements and...

www.tractorbynet.com

 

[mopwr2004a]

?About the glow plugs and relay/timer.
Does the instrument cluster light go off after the plugs are at temp like a diesel pickup?

 

[dieselscout80]

?About the glow plugs and relay/timer.
Does the instrument cluster light go off after the plugs are at temp like a diesel pickup?

Mine does.

 

[tmeric7]

There is no temperature measurement. The glow plugs run on a timer then go off after 4 - 10 seconds, depending on your tractor model. At that point, yes, the light goes out. If yours does not, that probably indicates that there is a bad ground in that circuit.

 

[keony]

?About the glow plugs and relay/timer.
Does the instrument cluster light go off after the plugs are at temp like a diesel pickup?

Yes, my light goes out about 4 seconds after I turn on the key, then I crank it.

 

[Williy]

You should be able to; use an volt/ohm meter set to ohm;s
if the needle don't more glow plug is shot

willy