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F1loco

Electric Fan Wiring

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So, it's time to put in the new cooling system.  Have the old Hayden that I took out a while back and trying to wire it up since I went with the skinny pulley kit.  Looks like the previous owner had the 30 and 87 leads swapped on the relay?  30 (red)  goes to the fan, while the 87 (orange) with inline fuse presumably went to hot.  Terminal 65 goes to ground.  There is a brown and green that comes off 87 (though the green is cut off) and the brown runs to one side of the probe.  There is ground wire off the other side of the probe that connects with an eye off the ground to the fan.  Presumably when the target temp is reached, the ground circuit is closed via the probe and hot lead (red) will reach the fan?

Question is I am not sure why only the single 12V source?  Most of the diagrams have an ignition on hot source and direct wire?  If I am only using the fused orange to hot, do I want constant 12v, or only ignition on (which I believe is brown/green) hot?  Looks like by the length it was probably wired up to the block of hot wires by the old control box (since removed now that I have a an alternator).  Don't know if if leaving it on a 12v constant hot would be better as it would run after the key is off like a modern car, or if that will be a battery killer in the long run and should only wire it to ignition on 12v source?

Finish line is in near.

-Don

Edited by F1loco

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The description isn't quite clear Don  - a sketch of the connections would help. The way you describe it, the relay doesn't seem to be doing anything. What is connected to 85 and 86, which is the relay coil connection?

30 and 87 on a single-throw relay are interchangeable since it's a simple 'make' contact, so it doesn't really matter which way round the connections are.  Of course it will matter if it's a changeover relay with something connected to 87a.

I would guess the system was originally wired so that the relay took the motor current rather than the controller and ignition switch?

Whether you should leave the system always 'live' depends on what the controller is and whether you trust it. If it's a simple electro-mechanical switch  it won't take any current when off.  An electronic one might draw some small current all the time it is connected. 

Edited by RobH

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Any Use?

https://wiringall.com/hayden-electric-fan-wiring-diagram.html

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Thanks, I think I have the diagrams all worked out, but still trying to decide, as I am not running a manual switch, do I want to connect the fused 12V to a constant hot (battery) or to a 12v to ignition on only - ie, do I want the fan to continue to run when I turn the key off like most modern cars would do, or just have it run while the key is on.  Not sure it matters much, just some drain on the battery I suppose if I choose option one, but it is updated with an alternator so I don't see charging be an issue.  

 

Don

Edited by F1loco

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Once the engine is stopped there is no circulation of the water, so not much point in running the fan in my opinion.

I would run "high current" wiring from permanant 12V (via a fuse) to the relay contacts, & then on to the fan.

Then lower current wiring from switched 12V (via a fuse, or take from existing fused ignition circuits) to one side of the relay coil, then connect the other side to the thermostat, which in turn is grounded. If you wish for an override switch this is connected across the thermostat.

Bob

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Hi Bob,

allowing the fan to keep running after the engine is off may help reduce the underbonnet temp a little quicker and may prevent evaporation of fuel in the carbs.

Roger

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41 minutes ago, Lebro said:

Once the engine is stopped there is no circulation of the water

Not strictly true. As long as the thermostat remains open there will be thermosiphon circulation of the water, since the water  pump impeller has clearance. 

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Valid point on the lack of pump running.  Guess for the gallon that could be "cooled" post ignition off doesn't justify the end.  I will go 12V hot ignition on and see how the temperatures hold.  Live in Florida and running around doing errands with a lot of stop and goes can cause it to creep up.  Many thanks.  Looking forward to getting it on the road now that's cooler - 55 tomorrow morning - woohoo.  Well at least for 3 hours and two days in a row.  LOL.

Don

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Hi Don, the cut off green wire probably ran to an override switch which would be connected to earth so when switched on it would provide earth to the fan same as probe does. I prefer a manual override switch because it allows you to quickly test the fan motor is working and also allows you to preempt the theroswitch when you can see the temp is about to climb, like at start of a long strep hill or a traffic jam. It is also easy to wire a fan on warning light to the override switch. Simply connect a warning light with a ign on live feed and let the override switch provide the earth when on. This will allow the warning light to come on whenever the fan is on, whether by theroswitch or manual, and only one additional single wire is needed from the relay to the override switch.

Chris

 

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