Carb Cooling Fan - Wiring Help (1 Viewer)

[GA Architect]

Has anyone ever used the below type of switch for any 12V power device in their 40?

I've installed a carb fan to my '77 FJ40 that is not original to it. Fan power to constant 12V power with in-line fuse, and the ground to a manifold temp sensor. The manifold temp sensor I've installed works fine, but the carb fan is running too long in my opinion (30 minutes plus). Thus I'm looking to add a timed relay to shut the fan off after 20 minutes of use.

In lieu of going with the Toyota Cooling Fan Relay I bought (no plug for it though), how about using this 20 minute relay? Seems like a simple set up for running the carb fan for only 20 minutes after turning the ignition off. I will have a on/off switch between the 12V constant power and the relay as a total override to shut off the system if needed.

NOTE: If the temp sensor stops working, I can always apply a constant ground for the fan. Then it would run every time I turn the ignition on/off. If the fan isn't needed (short trip or winter time), I can over-ride the module with the on/off switch.

 

[antFJ]

fyi the factory setup only has the fan on for about 60 seconds after shutting the truck off

 

[LAMBCRUSHER]

How much for that relay? you can get a 12 volt smart relay(mini PLC) for about 80 bucks from galco, or for about 50 bucks you can get a milti function multi voltage timing relay from a reputable electrical controls supply house(platt). the temp sensor is the trigger to a one shot contact that should run for about 20 minutes- or for 5 minutes after the trigger input in lost...another factet to this is that you will either need a stand alone relay to prevent the trigger from starting the cycle during running conditions, or you will need to use the programmable relay to have all the logic operated under one device. if you can find a 12 volt operated one shot timer and a 12 volt stand alone simple relay with spdt contacts for less than 50-60 bucks, then that would be the way to go...the basic relay is activated by the engine on signal(ig on - power to coil) and holds the contact OPEN while ignition has power, which prevents the temp sensor signal from reaching the trigger input to the one shot timer, thus, the fan will no have power unless the temp sensor is ON/CLOSED(high temp)AND AND the ignition switch(engine) is OFF/OPEN). does this help?

 

[LAMBCRUSHER]

fyi the factory setup only has the fan on for about 60 seconds after shutting the truck off

my 62 fan will run for almost 20 minutes post shut-down on the hottest days/ after hardest driving

 

[GA Architect]

How much for that relay? you can get a 12 volt smart relay(mini PLC) for about 80 bucks from galco, or for about 50 bucks you can get a milti function multi voltage timing relay from a reputable electrical controls supply house(platt). the temp sensor is the trigger to a one shot contact that should run for about 20 minutes- or for 5 minutes after the trigger input in lost...another factet to this is that you will either need a stand alone relay to prevent the trigger from starting the cycle during running conditions, or you will need to use the programmable relay to have all the logic operated under one device. if you can find a 12 volt operated one shot timer and a 12 volt stand alone simple relay with spdt contacts for less than 50-60 bucks, then that would be the way to go...the basic relay is activated by the engine on signal(ig on - power to coil) and holds the contact OPEN while ignition has power, which prevents the temp sensor signal from reaching the trigger input to the one shot timer, thus, the fan will no have power unless the temp sensor is ON/CLOSED(high temp)AND AND the ignition switch(engine) is OFF/OPEN). does this help?

LAMBCRUSHER,
This relay is about $50 bucks....If you look at the schematics, it seems to work just like the Toyota switch does. It only comes on after the ignition switch is turned off, and runs for 20 minutes.

NOTE: The thermo sensor has to ground out as well for the fan to come on.

 

[Pin_Head]

Get a Klixon 1NT Fan thermostat that closes at 160F and opens at 140 F. Put a relay in line with the thermal switch and fan to interrupt the current when the ignition switch is on. Mount the thermal switch near the base of the carb.

 

[GA Architect]

Get a Klixon 1NT Fan thermostat that closes at 160F and opens at 140 F. Put a relay in line with the thermal switch and fan to interrupt the current when the ignition switch is on. Mount the thermal switch near the base of the carb.

Attached is where I located my 195 degree 'ON' SPAL thermo sensor, with a 185 degree 'OFF'. The problem is, the carb fan runs in excess of 30 minutes. Thus the reason for the 20 'OFF' relay.

 

[Pin_Head]

You won't need a timer if you get the off temp right. I was just guessing, but if your runs for 30 minutes at 185, maybe you need on at 205 and off at 195 for your specific mounting location. You could find out the right temp by putting a temp probe at the location and monitoring the temp over the 20 minute time. Seems to me that the actual temperature is more important than how long the fan runs.

 

[GA Architect]

You won't need a timer if you get the off temp right. I was just guessing, but if your runs for 30 minutes at 185, maybe you need on at 205 and off at 195 for your specific mounting location. You could find out the right temp by putting a temp probe at the location and monitoring the temp over the 20 minute time. Seems to me that the actual temperature is more important than how long the fan runs.

Thank you for the input...I'll look for a 205/195 sensor and try that route first. Maybe I'll try some different mounting bracket options before I try to wire in a timed relay.

 

[antFJ]

my 62 fan will run for almost 20 minutes post shut-down on the hottest days/ after hardest driving

I should have said my 1978***

 

[N919HJ]

My 79 will run for 20 minutes or longer as well.

 

[GA Architect]

After a lengthy phone conversation with In-Power, and learning more than I cared too about electrical circuits, here is my final wiring diagram. This will be similar to the original Toyota set up, with the exception that my carb fan will turn on whenever the thermo sensor reads above 190, even while I'm driving the rig. Which isn't such a bad thing, in my opinion. But as soon as I turn off the ignition, provided the thermo sensor is over 190 degrees, the fan will only run for a maximum of 20 minutes or until the thermo sensor drops below 180, which ever comes first. Peace of mind knowing that the fan will shut off after 20 minutes of turning off the ignition.

NOTE: I'll also have the on/off switch to the 12V constant if I ever need to over-ride the circuit for any reason.

IIRC, the original Toyota "RED" Carb Fan warning sticker says: ......fan with automatically turn off within 30 minutes after shut down.

 

[fj401978]

My '78 runs for about 20 minutes (+) or (-) a few.

 

[sggoat]

If you have a source for an old toaster oven, you can cannibalize the timer from it. Hook it up to the power to the fan. Mount the switch/timer in the cab. When you shut the engine off, twist the timer to whatever time you want it to run(usu. 20 mins). This mod cost me zero, accept for my time.

 

[simps80]

The 20 minutes you recall on the sticker is correct.
Below is the post in my rebuild thread where the carb fan is

http://www.risingsun4x4club.org/forum2/showpost.php?p=251718&postcount=146

 

[GA Architect]

If you have a source for an old toaster oven, you can cannibalize the timer from it. Hook it up to the power to the fan. Mount the switch/timer in the cab. When you shut the engine off, twist the timer to whatever time you want it to run(usu. 20 mins). This mod cost me zero, accept for my time.

Only a 'goat' would cannibalize a toaster oven....

Having an engineering background, that is too simple of an approach.....I've got to make it as complicated as I can!

Note to self: Fall back Plan - (Manual Timer!)

 

[fantic]

GA Architect what temperature sensor did you end up using? The PO removed all of the fan relay wiring on my 79. Found all of it in a box except for the thermo sensor. I just grounded the blue wire and it works except it runs for 30 min. The thermo sensor is the last piece of the puzzle.

 

[GA Architect]

GA Architect what temperature sensor did you end up using? The PO removed all of the fan relay wiring on my 79. Found all of it in a box except for the thermo sensor. I just grounded the blue wire and it works except it runs for 30 min. The thermo sensor is the last piece of the puzzle.

fantic - With a little research, I found that gasoline boils around 185 degrees (+/-). Thus I removed the SPAL 195-TS and re-installed with a SPAL 185-TS degree 'ON' sensor, and 'OFF' at 165 degrees. Also, I received my 20 minute 'OFF' relay yesterday, so I'll wire that in this weekend.

 

[fantic]

Thanks. Just ordered one. Let you know how it works with the stock stuff.

 

[GA Architect]

I wired my InPOWER VCM-04-20MF in this weekend, as I diagramed above. Drove my 40 to work this morning, sure enough, the carb fan came on and it shut down about 20 minutes after I switched the rig off.

At least on it's first trial run, seemed to work just like a factory installed one.

Peace of Mind knowing my carb fan won't run too excessively and drain the battery.