CARB COOLING FAN – ON THE RIGHT TRACK? (with pix) (1 Viewer)

[TheHardWay]

Today or tomorrow will hit 100F here in Las Cruces, so it’s time to get this project off the ground. I have a 77 FJ40 I bought 3 years ago from a Tucson Mud member.

He’d had an OEM fan installed with no thermo sensor, no relay timer, and a toggle switch for manual operation. I knew from the 78 I previously owned how it was designed to work, so while cleaning out the engine bay I removed the fan and switch, intending to recreate the original setup, and I know, the 77 Federal model had no fan – but hey, I live in the desert and I’M NOT A PURIST.

I’ve cleaned and tested the fan and bought a relay timer and thermo sensor from other Mudders, so if I’ve learned anything from all the threads I’ve researched here, I just need to find a 78 carb cooling fan sub harness with original connectors – PLUG N PLAY, right?

Towards that Perfect World scenario, Plan A is to post a WANTED ad in Mud Classifieds in hopes of finding a fellow Mudder with a full 78 harness he no longer needs, who would be willing to separate the sub harness and sell it to me for a reasonable price.

Before I do that I would like some feedback from my Mud peeps here as to anything about the fan setup I missed or assembly tips or even suggestions for harness sources. Now, I am aware from research about several alternative (read: non OEM) systems - that will be Plan B.

What say you, Mudder Brudders? Can you help?

 

[mattressking]

You may not be a purist which is no problem, but the easiest method to incorporate factory parts would mimic factory installation. Does your '77 have the bracket in the passenger foot well behind the HVAC crossover pipe to mount? Would be two L shaped brackets. Next is just a quick subharness which is easily made with a few meters of wiring and a molex crimper. Since the oem relay has a specific connector you'd need to source that to make it easier to connect/maintain/troubleshoot. Easily grabbed from a partout or similar. Another option is even using a later cooling fan relay/timer or even one from a 60 series since they use the same manifold sensor and the fan is the same.

Quick and dirty if you use the '78 parts you'll need to do the following wiring for the cooling fan timer.

Pin 1 - Green/White to 5A fuse to 15A Stop (or any constant +12v source)
Pin 2 - Blue/Black to manifold temp switch
Pin 4 - Black/Yellow to +12v constant
Pin 6 - White/Black to ground
Pin 7 - Blue/Red to fan motor

Choose whatever colors you like for wires but for ease of troubleshooting and the next guy, it helps to match colors.

I've included '77 and '78 wiring diagrams for reference. A few slight variations but I'd just copy the '78 design if the relay you have is from a '78.

 

[Engineer8000]

the 76/77 cali fan control is indeed different from the 78 federal or 78 cali

76/77 cali vs 78 fed

78 cali

If I recall the only difference between the 78 fed vs cali is the temperature that they come on is higher for the cali version. Hence a fed controller can be recalibrated to operate as a cali box.

 

[Engineer8000]

here is a 76/77 installed

pretty sure this is the mount for the 78

 

[Engineer8000]

And the 76/77 cali used a thermoswitch vs a sensor that started in 78.

 

[mattressking]

That’s really good info! Thanks for all that @Engineer8000

 

[TheHardWay]

You may not be a purist which is no problem, but the easiest method to incorporate factory parts would mimic factory installation. Does your '77 have the bracket in the passenger foot well behind the HVAC crossover pipe to mount? Would be two L shaped brackets. Next is just a quick subharness which is easily made with a few meters of wiring and a molex crimper. Since the oem relay has a specific connector you'd need to source that to make it easier to connect/maintain/troubleshoot. Easily grabbed from a partout or similar. Another option is even using a later cooling fan relay/timer or even one from a 60 series since they use the same manifold sensor and the fan is the same.

Quick and dirty if you use the '78 parts you'll need to do the following wiring for the cooling fan timer.

Pin 1 - Green/White to 5A fuse to 15A Stop (or any constant +12v source)
Pin 2 - Blue/Black to manifold temp switch
Pin 4 - Black/Yellow to +12v constant
Pin 6 - White/Black to ground
Pin 7 - Blue/Red to fan motor

Choose whatever colors you like for wires but for ease of troubleshooting and the next guy, it helps to match colors.

I've included '77 and '78 wiring diagrams for reference. A few slight variations but I'd just copy the '78 design if the relay you have is from a '78.

View attachment 3353956

You mean this bracket?

I can fab an adaptor plate if needed.

 

[mattressking]

You mean this bracket?

View attachment 3354026

I can fab an adaptor plate if needed.

That’s the bracket yes, you can bolt the ‘78 relay right to it.

 

[micruz60]

Nice!

 

[TheHardWay]

Just posted in Classifieds: Wanted - ’78 FJ40 carb cooling fan wiring sub harness – or whole wiring harness! - https://forum.ih8mud.com/threads/78-fj40-carb-cooling-fan-wiring-sub-harness-or-whole-wiring-harness.1315679/

So if you know of anyone who might fit the harness profile, please let them know I'm looking.

Thanks guys!

 

[mattressking]

It’s wrapped into the wiring harness, you won’t find it separate as a sub harness.

Fastest way is just make one with a few meters of wire and a few plugs. If you don’t find anything - once I’m back stateside I could probably help you out with making a harness and use my truck as a template.

 

[TheHardWay]

It’s wrapped into the wiring harness, you won’t find it separate as a sub harness.

Fastest way is just make one with a few meters of wire and a few plugs. If you don’t find anything - once I’m back stateside I could probably help you out with making a harness and use my truck as a template.

I've been following your build thread since April last year when I suggested you give your firewall a good cleaning and if my classified doesn't yield results, I will gladly take you up on your generous offer. If I could just get a female relay timer control box plug, the rest would be easy (famous last words from TheHardWay).

 

[cruiserboy14]

You could contact @Coolerman to get the wires and plugs you need to fabricate your own sub harness. Then you know it’s good, new wiring.

 

[TheHardWay]

You could contact @Coolerman to get the wires and plugs you need to fabricate your own sub harness. Then you know it’s good, new wiring.

Yeah, I PMd him last Saturday - still waiting for a reply

 

[Engineer8000]

If you get in a bind, I have the controller plug and terminals. I'm sure you can source the others easily.

 

[TheHardWay]

If you get in a bind, I have the controller plug and terminals. I'm sure you can source the others easily.

View attachment 3354666

I'MINABIND I'MINABIND !!!!!!!

 

[MOTOV8R]

The relay and controller were separate units on my 79. Are they combined in earlier models?

 

[TheHardWay]

Check this out:

Repair of '79 - '80 carb cooler fan controller circuit board

My '79 40 didn't have the blower for the carb when I got it about 6 years ago. Until recently I was ignoring my hard-starts after the engine was warm and then sat for a while. I started reading the LONG threads about guys on MUD getting their carb coolers working and having much success with...

forum.ih8mud.com

You're welcome!

 

[MOTOV8R]

Check this out:

Repair of '79 - '80 carb cooler fan controller circuit board

My '79 40 didn't have the blower for the carb when I got it about 6 years ago. Until recently I was ignoring my hard-starts after the engine was warm and then sat for a while. I started reading the LONG threads about guys on MUD getting their carb coolers working and having much success with...

forum.ih8mud.com

You're welcome!

Thanks for the info. I was just wanting to make sure you weren’t missing the relay.

 

[TheHardWay]

AND NOW, THE REST OF THE STORY​

Plan A did not pan out (no surprise there), but a couple of Mudder Brudders stepped up and helped me get going with Plan B.

What I did​

I already had the fan, control relay box and thermo sensor:

All I needed were a control box male plug and wire terminals, 18 gauge wiring and a 5 watt in-line fuse.

I had tested the fan directly to the battery and it worked. My control relay unit looked pretty good, but I had no idea if it worked, so I sent it to @Engineer8000 for inspection. He replaced the capacitor and two diodes and sold me a control box male plug and a supply of terminals. To have the 5 factory wire colors and stripes I bought a supply of them from Coolerman.

Okay then, all set and ready to go!

And right away I got stuck. I knew I’d be connecting wires to Pins 1,2,4,6 & 7, but which of these was Pin 1?

I ran Mud and Google searches with multiple key words, and found 12 threads worth saving for study. It appears I’m the only dope who has tried building a carb cooling fan system from scratch using only Toyota parts. Yeah, that’s me – TheHardWay!

First, I tried the logical approach:

Hahaha, foolish American. Then @mattressking sent me what proved to be the rosetta stone for carb cooling fan controllers (Fig. 15.8).

Carb Cooling Fan

Of course - I should have followed Toyota logic - duh!

We'll pause briefly while I load more pics.