Ignition hot circuit

[Sumitso]

I recently put a 2200 CFM electric fan on my radiator. After some perusing the electrical schematics, I tapped the 30A line for the heater as my ignition hot circuit for the fan and it's thermometer. The odd thing is that now that I have done this, the engine about 25-30% of the time (when hot) will continue to idle for about 10 or so secs when the ignition has been turned off.

Now my question is this, is there a better circuit tap for ignition hot or a better method to use? I'm researching some battery isolators/combiners to see if they have an off/on ignition hot function. I'd like to take care of the small issue that has suddenly cropped up for certain.

The end plan is to have a good circuit to tap, so I can install a secondary fuse box which is turned on by a relay for optional items such as a winch, lights, lowrance gps, and maybe one of those ridiculously expensive freezer fridges .

 

[roscoFJ73]

What was wrong with original set up?

 

[Sumitso]

I'm guessing that you meant the original fan with your question. There are pros and cons to both electrical and mechanical fans; the cons to the mechanical outweigh the electrical to me. Loss of hp, added torque and wear on the water pump, inconsistent cooling since the fan speed is dictated by rpms, chance of radiator puncture in a sudden--not slow water crossing(had this happen to me), better cooling at low speed or idle, fan on constantly.

I know the argument against electric is that they can fail, but any part can fail. It is a simple dc motor, which has been proven to last for a long time. The viscous clutch on a mechanical fan can go out; and has before with my old FJ40...twice.

I love the toyotas, especially the landcruisers, but the use of a mechanical fan is not of the better ideas to carry over to modern vehicles, nor is the idea of having to dump oil all over the place when changing the filter.

 

[roscoFJ73]

There are pros and cons to both electrical and mechanical fans; the cons to the mechanical outweigh the electrical to me. Loss of hp, added torque and wear on the water pump, inconsistent cooling since the fan speed is dictated by rpms

I cant see how the HP loss comes into the equation.Electric fans use electricity and your alternator has to work harder to recharge the battery.Whichever way you go ,it takes a certain amount of energy to run the fan to pull enough air through

The water pump is designed to take the strain of the fan,mine lasted 250000klms and most go longer.
The fan only works at lower speeds,as the speed of the airflow increases with the speed of the vehicle ,the fan does not work so hard and eventually just free wheels.
I think they also have a heat sensitve spring in the fan hub,so less heat,less torque is applied to the fan.

chance of radiator puncture in a sudden--not slow water crossing(had this happen to me),

This is breaking one of the 1st rules of offroading,I wouldnt do it because of the risk of hydrolocking the engine.

better cooling at low speed or idle, fan on constantly.

I live in a part of the world that is as hot as Arizona and I go offroad on the hottest days and never have a problem.
Its really about keeping the coolant pressurised and a bit of driving skill.

I love the toyotas, especially the landcruisers, but the use of a mechanical fan is not of the better ideas to carry over to modern vehicles, nor is the idea of having to dump oil all over the place when changing the filter.

Toyota are still using mechanical fans on their landcruisers AFAIK while they have switched to electric fans on their car range.
Its more to do with weight savings and more space in the engine bay that any other reason,but on a 2 ton vehicle,half a kilo and a centremetre or 2 is nothing.

As for your fan problem ,I would run it from the power outlet in the engine bay or direct from the battery and activate it from a relay.