Carb Cooling Fan - Wiring Help

[myquestoyota]

Here is mine, looks like fed spec

 

[Coolerman]

I'm not sure if that means you are or are not a Fed spec vehicle. Any sticker experts on today?

 

[Pin_Head]

It will say CA or Fed on the ID tag.

 

[myquestoyota]

I see the Fed Spec mentioned here on MUD. What does that mean as opposed to the USEPA on mine or the CA Spec? Just curious.

 

[FishTacos]

This is a great thread. I'm no help at all but I am glad to see this because I tried to get my fan working on my 60 and was totally stymied. Never realized there was a fuse under the wrapping. Thanks guys.

Also, glad to see you have some free time on your hands, @Coolerman. Welcome back.

 

[SteveH]

My FJ40 ('78) fan runs for 25 min. or so, and is critical to preventing hot soak issues when parking the truck on a hot day. The PO hot-wired the fan with a switch, but did not use a DPDT switch, and the 12v backfeed fried 2 diodes in the Toyota fan computer/timer. I replaced those diodes and tossed his manual switch.

Beware that when you hot wire the fan to run with a switch from the battery, you need to isolate the fan computer from the 12v you're feeding directly to the motor (using a DPDT switch or some technology). The good news is that my 'fix' using two Radio Shack diodes has now lasted over 20 years.

 

[PabloCruise]

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.

Good stuff - thanks Pin Head.

 

[tls3601]

Great stuff I am getting ready to get a cooling fan on my '78, PO removed it and lived in Phoenix......go figure!!!!

 

[myquestoyota]

Can you draw me a picture pinhead? (schematic)

 

[GA Architect]

Thanks for the info on the diode.
I think this might make a good "kit" for those that do not have the OEM Cooling Fan Timer Module or have it and it doesn't work. If I can find a source for the matching female OEM timer module connector, it would be easy to make a plug and play kit assuming they had the temp sensor already and it actually works... Lot of if's in that statement! Of course a replacement sensor could be gotten... Something for me to ponder on...

Coolerman,
I finally put together the adapter that will plug into the Waytek 20 min relay I'm using for my Carb Fan. Using the Waytek #31073 Terminal for Relay Connectors, they just clipped into the adapter very easily. Here is what it looks like.

 

[ColonelMustardFJ40]

GA - I am curious why didn't you use the 12 volt logic inputs?

 

[GA Architect]

GA - I am curious why didn't you use the 12 volt logic inputs?

Colonel,
Pardon my ignorance, but I'm not sure what the "12V logic inputs" you reference are.

 

[Coolerman]

Coolerman,
I finally put together the adapter that will plug into the Waytek 20 min relay I'm using for my Carb Fan. Using the Waytek #31073 Terminal for Relay Connectors, they just clipped into the adapter very easily. Here is what it looks like.

Looks great! I see they did include the correct terminals. That is exactly what I would have done with the diode also. Fold a piece of tape over the exposed diode when you mount it to prevent shorting it out accidently. I have had no luck sourcing the odd connector for the fan module or its mating harness connector.

 

[Coolerman]

This is a great thread. I'm no help at all but I am glad to see this because I tried to get my fan working on my 60 and was totally stymied. Never realized there was a fuse under the wrapping. Thanks guys.

Also, glad to see you have some free time on your hands, @Coolerman. Welcome back.

Yeah, I'm between jobs at my day job for a while so I can surf MUD a lot more often!

 

[ColonelMustardFJ40]

The logic inputs are pins 87a and 87 and are low current inputs that are meant to interface to your thermo sensor or a manual switch to manually turn the fan on/off, if desired. A concern I have about your configuration is the maximum current spec for the SPAL switch. The SPAL specs are: Max. Current & Voltage: 3 amp, 32VDC, grounded case only (https://webstore.spalusa.com/en-us/...es/185-ts/temperature-switch-185-degrees.aspx). Not sure but I think the cooling fan may approach that current level, or even exceed it. Who gave you this design?

 

[ColonelMustardFJ40]

Just one more comment: if you look at the way SPAL recommends using the thermal switch, it is not in series with the fan, it is used as sensor for their controller not a high current switch.

 

[GA Architect]

The logic inputs are pins 87a and 87 and are low current inputs that are meant to interface to your thermo sensor or a manual switch to manually turn the fan on/off, if desired. A concern I have about your configuration is the maximum current spec for the SPAL switch. The SPAL specs are: Max. Current & Voltage: 3 amp, 32VDC, grounded case only (https://webstore.spalusa.com/en-us/...es/185-ts/temperature-switch-185-degrees.aspx). Not sure but I think the cooling fan may approach that current level, or even exceed it. Who gave you this design?

Colonel,
Logic inputs 87 & 87a - based on the In-Power (Waytek) schematic, by connecting the 12V switched power to the 87a terminal, this will provide power to the circuit and once this 12V switched power is removed, the relay will stay powered for only 20 minutes by the connection of the fused 12V constant. I'm guessing that it works just like setting a timer on a toaster oven...Seems to be working that way.

As for the SPAL 185-TS; It is obvious that I'm not using this switch the way it was intended. However, I took for granted that the carb fan wasn't drawings more than three amps. This switch is for running a cooling fan (albeit a fan for the radiator), thus logic told me I could use it. But my logic isn't always to be trusted....Are you telling me that I shouldn't use this switch? Does Toyota still sell the thermo switch I'm trying to replicate? I couldn't find a new one anywhere on the internet.....I guess if this Thermo Switch goes out, I'll install my Klixon 1NT unit.

 

[ColonelMustardFJ40]

If your fan draws less than three amp your configuration should be reliable. I will measure the operating current for the cooling fan tomorrow and let you know what it draws. If you look at the SPAL application notes, it does show the thermal switch as a low current input to their controller and the higher current for the fan motor is a separate output, similar to the VCM controller that you are using. Also the spec sheet for the VCM describes the 87 and 87a as 'a logical exclusive OR' (I would assume that there are pull-ups inside). Just saying.

 

[tls3601]

Great stuff! Not to hi-jack, but going thru the same process as you. Does anyone know if the cooling fan relay part #85927-60021 designed for as 79-80 will work with a '78, the mating plug looks identical?

 

[sggoat]

myquestoyota: Do you know if your truck is a California emissions spec truck? Reason I ask is all the 77 schematics I have and the actual 77 harness I have do not show the Carb Cooling Fan System. That must mean the cooling fan was only on California spec trucks.
So... I need a 1977 schematic for a California Emissions spec truck! Do you, (or anyone else reading this thread) have a 1977 FJ40 California spec schematic? Maybe this is in the Emissions manual for the 2F?

My truck is a Ca. one-purchased in Sept '77 by my wife's sister. it came with a large wiring diagram(but for some reason the diag says 78 on it) . The truck was desmogged years ago, but the cooling fan connectors are still there.--up front-driver's side - light green connector. The cooling fan relay is located under the psngr side fresh air duct , on the firewall(as well as the wrapped 5 amp fuse Mr. Toyoda put in). Was not able to get the relay to work, so I installed a scavenged bilge blower from a Searay boat and mounted it as close to the orig as I could.--works great(has a scavenged mechanical toaster over timer to make it run)!
If I can scan the large diagram, will post it(prob in pieces)