blowing main fuse tc33d

[pvhogie]

i have a tc33d that keeps blowing the main fuse. I think it has somehting to do with the glow plugs or the relay/resistor. I have put a staple in place of the fuse just to get it started and that thing gets cherry red. Any help?

 

[beenthere]

Put a light bulb on a jumper in the main fuse, and work on finding the cause of the short (when the light bulb goes out). Possibly you can find a way to disconnect a wire at a time to trace it out.

 

[pvhogie]

the problem only exists when i put the ignition switch to preheat before i start it. maybe ign. switch?

 

[SteveInMD]

Two components that have been problematic on this tractor are the ignition switch and the glow plug timer relay. So, yes, your ignition switch may be bad. Also the circuit that energizes the starter solenoid is poorly designed. It behaves oddly and makes troubleshooting electrical problems difficult. Performing the modification described in the attached PDF file makes the starting circuit utterly reliable and may solve your problem. If not, it at least makes further trouble shooting much more doable. I believe the current design causes the circuit to draw a little more current then ignition switch can handle so it fails over time.

 

[RickB]

Performing the modification described in the attached PDF file makes the starting circuit utterly reliable and may solve your problem. If not, it at least makes further trouble shooting much more doable. I believe the current design causes the circuit to draw a little more current then ignition switch can handle so it fails over time.

It is possible, although highly unlikely the OP's symptoms are related to this. An ignition switch failure is a possibility, although it would be related to the glowplug circuit contacts. Other possibilities would be a dead short in a glowplug itself, or a piece of tramp metal contacting the glowplug buss bar and the engine, causing a dead short in the glowplug circuit. Examine the strap connecting the glowplugs to be sure it is not shorted out somewhere. Then disconnect the wire feeding #3 glowplug and see if the short circuit persists with the glowplugs disconnected from the circuit. I've not seen a faulty lamp timer relay cause the main fuse to blow, but there is a first time for everything.

 

[pvhogie]

thanks, i will try troubleshooting this afternoon.

 

[pvhogie]

I have disconnected the wire to the glow plug strap. The fuse no longer blows. When I put the ohm meter on the plug strap and get continuity. I guess there is short in the plugs, just which one?

 

[RickB]

Remove the strap connecting the glowplugs, then test each glowplug with your ohm meter. The terminal at the top of each plug should have about 1 ohm of resistance to a clean ground on the engine. Do not remove to test.

 

[thclimer]

Pvhogie,

I hope you are able to find which glow plug is causing your problem and it's a easy fix.

Just out of curiosity what is the average life of a glow plug?

Tim

 

[pvhogie]

problem solved. i took the glow plug strap off and cleaned all connections on both strap and plugs inside and out. I measured with amp meter after put it back together and got 32 amps initial then immediately dropped to lower 20 amps. No longer blow fuses. Ohms and all other checks come out ok too both before and after cleaning everything. Might have been caused by the recent pressure wash?