Carb Cooling Fan - Wiring Help (1 Viewer)

[Coolerman]

Excellent research and implementation. Perfect for those that don't have a working OEM Carb Fan Timer. One question, did they explain the purpose of the 1N4003 diode between ground and the output?

 

[GA Architect]

Excellent research and implementation. Perfect for those that don't have a working OEM Carb Fan Timer. One question, did they explain the purpose of the 1N4003 diode between ground and the output?

Coolerman,
The reason for the 1N4003 diode was for when the switch turns off, and fan spins for a second or two, it actually works as a generator producing electricity. So to protect the new In-Power switch from power coming back off the carb cooling fan, the diode is installed to ground that off. The diode has to be installed a certain way for it to work. The diode has a strip on one end, that has to be connected to I believe the ground, but need to verify my diagram at home the #30 power post.

That was the explanation I was given by the tech at In-Power. Note, he's never had this switch used for this purpose and was more than willing to provide any in-put/help for me to get it installed. He wanted to see pictures of it after I finished.

After a week, it seems to be working as planned. Piece of mind when I get out of my rig and hear it running. I've gone back 25 minutes later to check to make sure it is off, and each time it's been off.

 

[fantic]

Well so far so good. I made a bracket similar to the stock one. The Spal 185 sits about a half inch from the exhaust manifold behind the carburetor. Drove 10 miles into town and shut it off and the fan ran for about 10 min. Came home and it ran for 15 min. Soon as it shut off I opened the hood and took my heat gun and read 190 deg F on the intake below the carb. It read 155 on the float bowl area on the carb. After 10 min the temps went back up about 10 deg and then went back down.

 

[GA Architect]

Well so far so good. I made a bracket similar to the stock one. The Spal 185 sits about a half inch from the exhaust manifold behind the carburetor. Drove 10 miles into town and shut it off and the fan ran for about 10 min. Came home and it ran for 15 min. Soon as it shut off I opened the hood and took my heat gun and read 190 deg F on the intake below the carb. It read 155 on the float bowl area on the carb. After 10 min the temps went back up about 10 deg and then went back down.

fantic - Great to hear. As long as the bowl on the carb isn't getting over 185 (+/-) degrees to boil off the fuel, then the carb fan & sensor are doing their job.

 

[Coolerman]

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...

 

[myquestoyota]

I need to troubleshoot my system someday and this is all good info, thanks for all of the leg work GA.

 

[Coolerman]

I need to troubleshoot my system someday and this is all good info, thanks for all of the leg work GA.

First thing to check is the 5 amp fuse that is part of the plug near the Timer module. Most folks don't even realize there is a fuse there as Mr. Toyota taped it up.

 

[myquestoyota]

Thanks. Considering I just had the engine/tranny out including the cover it would have been an optimum time to root around under there but alas I didn't (again). I have a sensor but it is located on top of the intake manifold and includes a clip for the PCV hose. Is that the one I am using or is there another below (non existant)? It has headers on it so no stock exhaust manifold.

 

[Coolerman]

Now I'm not an expert on the various harnesses but on a 78 there are two thermo sensors. One is the manifold temp sensor for the carb fan and the other is the Emmissions Computer Carb Flange Temp Sensor. They have completely different connectors for them.

 

[myquestoyota]

I am thinking that on my 77 the sensor I have is the the emissions one and the other is MIA. My fan has the light green connector, the same color as the carb temp sensor but I have not seen unused connectors that would have gone to the missing sensor. More investigation is warranted. Thanks

 

[Coolerman]

Looking at my 1977 documentation would lead me to believe that the 77 did not come with the carb fan system? (Again Toyota changed harnesses like women change shoes...) What month is your 77?

 

[Coolerman]

Duh... just reread your post and you said you did have the fan. I take it you have the Timer module under the dash also?

 

[myquestoyota]

I have not rooted around under the dash for that but mine is a Jan 77 with the fan. I also have the emission "computer" box, what am I looking for in the way of the timer module? So I can check when I look for the fuse.

 

[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 - Here is an update on the In-Power switch. In-Power doesn't sell the switch, Waytek Inc. does ( http://www.waytekwire.com/item/85526/SOLID-STATE-OFF-DELAY-TIMER/ ). Waytek also sells a female plug, possibly for this switch( http://www.waytekwire.com/item/75281/MINI-RELAY-CONNECTOR/ ). The only item would be the 1N4003 diode connection, which actually has the striped end towards the male power post #30 (output).

Waytek is sending me a few of the female connectors to see if I can get a better connection than the attached photo below. The only item will be to figure a clean install of the diode. I think I can crimp the diode into each female plug along with the wire and just install into the new combined plug.

In the photo below, you can see my ON/OFF override switch I have between the fuse panel to in-line 15A fuse, ON/OFF switch to male plug #86 on the 20 minute relay. It is hidden unless you know where to look.

YES, that is plumber's tape I used to fab the bracket so it was adjustable. Also, I don't care to put anymore holes in my 40 than what it originally came with.

 

[Coolerman]

I have not rooted around under the dash for that but mine is a Jan 77 with the fan. I also have the emission "computer" box, what am I looking for in the way of the timer module? So I can check when I look for the fuse.

Here is what you are looking for. Note the fuse holder wrapped up in yellow tape...

 

[Coolerman]

Coolerman - Here is an update on the In-Power switch. In-Power doesn't sell the switch, Waytek Inc. does ( http://www.waytekwire.com/item/85526/SOLID-STATE-OFF-DELAY-TIMER/ ). Waytek also sells a female plug, possibly for this switch( http://www.waytekwire.com/item/75281/MINI-RELAY-CONNECTOR/ ). The only item would be the 1N4003 diode connection, which actually has the striped end towards the male power post #30 (output).

Waytek is sending me a few of the female connectors to see if I can get a better connection than the attached photo below. The only item will be to figure a clean install of the diode. I think I can crimp the diode into each female plug along with the wire and just install into the new combined plug.

View attachment 929399

In the photo below, you can see my ON/OFF override switch I have between the fuse panel to in-line 15A fuse, ON/OFF switch to male plug #86 on the 20 minute relay. It is hidden unless you know where to look.
View attachment 929400

YES, that is plumber's tape I used to fab the bracket so it was adjustable. Also, I don't care to put anymore holes in my 40 than what it originally came with.

Waytek is a great company. I do a lot of business with them. The relay socket they are sending you is a standard relay socket. Hopefully they are sending you the terminals that fit it also? If you can't get a good crimp on the diode lead and wire together in the relay terminal, do this: Crimp a short piece of wire with the other wire in the terminal, then solder the diode to that. Use heat shrink over the diode to insulate it. I think I will order one of those timers next time I place an order and see if I could come up with a plug and play kit. Appreciate the continuing feedback on this. Today I have nothing to do but surf MUD! Been too long since I hung out here on a regular basis...

 

[myquestoyota]

Hey Mark, let us know when you need a test dummy. That'd be me.

 

[Coolerman]

Hey Mark, let us know when you need a test dummy. That'd be me.

Will do!

 

[Coolerman]

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?

 

[myquestoyota]

I do not know if my truck was california emissions truck but it was desmogged before I got it. How can I find out?