TC33D pre-heat

[IllinoisTC33oper]

Hi,

I just went out to do some work with my 2004 NH TC33D. After starting, the glow plug pre-heat light stays on continuously. I have not done any diagnostics (yet). Just wondering if anyone had ideas off the top of your head?

Thanks,

 

[Tazz]

I believe that light is for a 5 second relay showing the key switch is in the Heat position yet actually may have no bearing on whether the glow plugs are getting hot or not its just showing power. The relay or part of it is most likely stuck closed.

The relay is on the backside of the firewall, not the engine side, and pretty easy to get to by removing the clamshell panels under the steering wheel.

If it's not the relay then maybe the key switch?

 

[IllinoisTC33oper]

Thanks, Tazz. I'll dig into it tomorrow.

 

[Tazz]

Thanks, Tazz. I'll dig into it tomorrow.

I posted this in the wrong thread
Hope it helps.
See attachment

 

[IllinoisTC33oper]

Awesome, looks like I am safe to run even with the lamp lit until I can dig into it.
Thanks, again!

 

[Tazz]

Awesome, looks like I am safe to run even with the lamp lit until I can dig into it.
Thanks, again!

The last statement on the test is what concerns me because when testing they hot wire it. So for it to illuminate or stay lit that means it still has power. The light relay may be bad and the light is staying on but why is it still getting power when the key switch is in the run position? If I can find more testing I'll post it here.

Cheers.

 

[Tazz]

I got back to the shop and found two more pages for troubleshooting the Heat Circuit.

 

[IllinoisTC33oper]

Tazz, I took out the Lamp Timer/Glow Plug Controller and tested per the manual, it was bad. My local NH dealer had a couple on the shelf so I put in a new and am good to go. (expensive little bugger!)
Thanks for your help!