Oliver 1850 temp sender causing blown fuse

[Alex Moix]

I have an oliver 1850 diesel that uses a 3 amp fuse to connect the accessory on the starter switch to the water temp gauge. I found that as I take the temperature sending unit for the gauge and screw it into the engine block, then the fuse blows. I assume this means the engine block is acting as a ground when it shouldn't be. How should I go about fixing this?

 

[super99]

Is this a new sending unit? I think the engine block is supposed to be the ground on a single wire set up.

 

[Jim.ME]

I have an oliver 1850 diesel that uses a 3 amp fuse to connect the accessory on the starter switch to the water temp gauge. I found that as I take the temperature sending unit for the gauge and screw it into the engine block, then the fuse blows. I assume this means the engine block is acting as a ground when it shouldn't be. How should I go about fixing this?

Sounds like the wires are reversed at the gauge. Is the power wire on the sender terminal of the gauge? That would make a dead short when the sender was in the block. Or an old gauge might have gone bad.

 

[scootergmc]

It does sound like a short. Do you still have a fuel gauge? The power should be coming from the fuse, to the fuel gauge, then to the temp gauge. Do you need a wiring diagram?

 

[Alex Moix]

It does sound like a short. Do you still have a fuel gauge? The power should be coming from the fuse, to the fuel gauge, then to the temp gauge. Do you need a wiring diagram?

Im currently waiting on a new fuel gauge since the old one was original to the tractor and no longer functions since the needle is stuck on empty. In the meantime im just bypassing it. As for the wiring diagram, i already have one. thanks though

 

[Alex Moix]

Is this a new sending unit? I think the engine block is supposed to be the ground on a single wire set up.

it is a new universal unit. This is what I got: https://www.yesterdaystractors.com/1042944_Temperature-Gauge_9588.htm
Here is a picture of the back:


Instead of just two terminals, it also has a permanently fixed black line (center of gauge) just for the sending unit attached at the other end of the line. The other 2 terminals are unmarked.

 

[Alex Moix]

Sounds like the wires are reversed at the gauge. Is the power wire on the sender terminal of the gauge? That would make a dead short when the sender was in the block. Or an old gauge might have gone bad.

Its a new gauge (see my reply to super99) but it has a dedicated line for the sending unit in addition to the 2 terminals. I think this may have something to do with it and i probably just messed up the wiring since im not completely familiar with this kind of universal gauge.

 

[Jim.ME]

it is a new universal unit. This is what I got: https://www.yesterdaystractors.com/1042944_Temperature-Gauge_9588.htm
Here is a picture of the back:

View attachment 72905
Instead of just two terminals, it also has a permanently fixed black line (center of gauge) just for the sending unit attached at the other end of the line. The other 2 terminals are unmarked.

First off that is not an electric gauge. the capillary tube between the gauge and sensor bulb are not supposed to carry current. If installing the sensor bulb is blowing a fuse you better be checking your wiring to the diagram. The only way that gauge should be connected to a power source is if it has a light inside of it, then the gauge might need a ground wire, right at the gauge. It has two mounting studs for a bracket, not terminals for wires.

Also, if the fuel gauge you ordered is not the right ohm range for the original sending unit (if you are using the old sender) if may not read/work correctly.

 

[Alex Moix]

First off that is not an electric gauge. the capillary tube between the gauge and sensor bulb are not supposed to carry current. If installing the sensor bulb is blowing a fuse you better be checking your wiring to the diagram. The only way that gauge should be connected to a power source is if it has a light inside of it, then the gauge might need a ground wire, right at the gauge. It has two mounting studs for a bracket, not terminals for wires.

Also, if the fuel gauge you ordered is not the right ohm range for the original sending unit (if you are using the old sender) if may not read/work correctly.

Ah I see. Well no wonder the fuse blows. I just mindlessly wired it to the mounting studs without realizing what I was even doing!

As for the fuel gauge, Im going to try to keep the old sender and hopefully it all works together but if not i will figure something else out. Thanks for your help!