myquestoyota
SILVER Star
Mine has issues even here in the PNW winter. I'm going to pull the sensor and refloat the connections next I think. Having never "reflowed" anything, any tips for a newbie?
fj40 carb cooling fan...do you run yours? (3 Viewers)
- Thread starter michaelharrisco
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Ok. One of my many items on my list to get done this winter was to get a carb cooling fan set up. I acquired the fan but it took a bit to see if my 01/76 had the rest of the components, which it turned out that it did not.
I ended up sacrificing the washer bottle location for the fan and built a small bracket to mount it there. I have never seen the piece that connects the fan to the side louver but was able to make a 4" boot to duct between the fan and the louver. Purchased the Derale adjustable fan controller that adjusts from 150-240 degrees. It has a 10 degree dead band which seems to work pretty well. I ended up installing it up under the dash by the seatbelt buzzer.
I temporarily installed the sensor above the manifold and had to move it closer to the carb. Once I find that spot where it seems to get the right temp, I will make a permanent bracket for the sensor.
Now that it has been getting warmer, I have been playing with the temperature adjustment slowly adjusting it up to a higher temp. I must say that it has made a big difference in hot starts and the first couple minutes after the motor is running.
The only concerns that I do have are, 1) I might need some kind of timer as on hot days I have come out after about 45 mins and it's still on. 2) I think I need some kind of relay put in the mix to make sure it does not come on while the engine is on. Not sure if that's really an issue.
I ended up sacrificing the washer bottle location for the fan and built a small bracket to mount it there. I have never seen the piece that connects the fan to the side louver but was able to make a 4" boot to duct between the fan and the louver. Purchased the Derale adjustable fan controller that adjusts from 150-240 degrees. It has a 10 degree dead band which seems to work pretty well. I ended up installing it up under the dash by the seatbelt buzzer.
I temporarily installed the sensor above the manifold and had to move it closer to the carb. Once I find that spot where it seems to get the right temp, I will make a permanent bracket for the sensor.
Now that it has been getting warmer, I have been playing with the temperature adjustment slowly adjusting it up to a higher temp. I must say that it has made a big difference in hot starts and the first couple minutes after the motor is running.
The only concerns that I do have are, 1) I might need some kind of timer as on hot days I have come out after about 45 mins and it's still on. 2) I think I need some kind of relay put in the mix to make sure it does not come on while the engine is on. Not sure if that's really an issue.
Component ID on the Fan Relay Module
I've been trying to sort out the carb fan on a 78 FJ40 with no success. I replaced a blown fuse in the in-line holder with a good 5A fuse, tested the fan with 12V to ensure it works, disconnected the temp sensor and and grounded its lead. Assuming everything works (according to the manual), the fan should come on when the ignition is switched from on to off. No joy. I pulled the relay and opened it up to find the burnt components you see in the bottom right of the picture. Two diodes(?) on the burned portion of the board almost fell off having bad solder joints. I re-soldered but even the trace itself is damaged on the other side from the failure. (The fuse in the in-line holder I replaced was a blown 15A fuse.)
Before I source a replacement relay module, can someone identify the two components on the lower right burnt part of the board? Thanks.
I've been trying to sort out the carb fan on a 78 FJ40 with no success. I replaced a blown fuse in the in-line holder with a good 5A fuse, tested the fan with 12V to ensure it works, disconnected the temp sensor and and grounded its lead. Assuming everything works (according to the manual), the fan should come on when the ignition is switched from on to off. No joy. I pulled the relay and opened it up to find the burnt components you see in the bottom right of the picture. Two diodes(?) on the burned portion of the board almost fell off having bad solder joints. I re-soldered but even the trace itself is damaged on the other side from the failure. (The fuse in the in-line holder I replaced was a blown 15A fuse.)
Before I source a replacement relay module, can someone identify the two components on the lower right burnt part of the board? Thanks.
Yes they are diodes, mine were the same way when I opened it up also. I just replaced them.
Hopefully the damage is limited to those two diodes. Do you know their values?
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I have a header on mine and the sensor is gone. If I ground the temp sensor, will the fan run on a timer? Thank you.
I'm not the expert but from what I've read, the fan control relay will run the fan for no longer than ~30 min regardless of the sensor's output to the controller. Someone please chime in if I'm wrong on that.
My 78 FJ40 is almost stock with the exception of a CA-smog Downey header. I hoped that the temp sensor being so far from the heat source was the reason the fan never came on but the relay module appears to be my problem.
I have the same year 78 and I have the same issues, if I run two wires from the battery and connect them to the fan it powers on, I have not opened up the fan cooling relay box. Can you send me a few pics from under your hood, the previous owner added some grounding wires and I'm not sure which ones are stock and which ones are extras.
One of these may help. Those look like the glass type that is mentioned.
http://www.tpub.com/neets/book7/24k.htm
http://www.ehow.com/how_7679008_identify-diode-markings.html
There looks to be others on the board that are identical. Take it to an electronics supply place and ask. Radio shack may do in a pinch if you find someone who has knowledge beyond cell phones and magic jack.
Please do post up your results, win or lose.
http://www.tpub.com/neets/book7/24k.htm
http://www.ehow.com/how_7679008_identify-diode-markings.html
There looks to be others on the board that are identical. Take it to an electronics supply place and ask. Radio shack may do in a pinch if you find someone who has knowledge beyond cell phones and magic jack.
Please do post up your results, win or lose.
I think that if you have a header, you don't need the fan.
I don't think you ever really need the fan. Probably if you were making deliveries, with lots of 10 minute stops on a hot day. It could save your manifold from cracking, but maybe not even that.
I do think it's a good idea and hearing it running is pleasantly nostalgic, IMO.
One pic is of the temp sensor and its mounting bracket. The original wire was damaged and I replaced with what I had handy, a white one. The other picture shows the bracket mounted. If you start at the bottom of the picture, you see the red wire to the brake master cylinder and the blue one for the temp sensor. Follow the blue wire to the coupling and then the white wire points toward the bracket with the sensor hidden from view. You can see the mounting bolts near the center of the picture.
I only have one red wire to the
Master cylinder, I can see where one used to be. Also the alligator clip is soldered to the other connection. Do I need both red wires going to the master cylinder and should I just cut the alligator clip wire off? Thanks for your time
Does someone happen to have a picture of the fuse under the dash? I have an AC system in the way and was hoping maybe I could get to the fuse through the ash tray hole. I can see some yellow tape back there, but no fuse.
Curtice
SILVER Star
I cannot find the inline fuse behind the ductwork either. Any pics or other help would be great.
Edit, mine was actually in my engine bay (I think).
Fuse looked good, I replaced it anyway. Still doesn't work. My fan motor is good when hooked to the battery. I tried grounding the wire that goes to the sensor as some suggested, but that doesn't work.
I was hoping it would be a simple fix...
Edit, mine was actually in my engine bay (I think).
Fuse looked good, I replaced it anyway. Still doesn't work. My fan motor is good when hooked to the battery. I tried grounding the wire that goes to the sensor as some suggested, but that doesn't work.
I was hoping it would be a simple fix...
Last edited:
Here's a pic with the duct removed. The Fan Timer is not pictured (removed for repair) but you can see the plug and the white, plastic, fuse holder. Well, it would be white if there were no blue overspray on it. Should be a 5A fuse in there. Mine had a blown 15A fuse. Probably why my fan timer is fried.
One of these may help. Those look like the glass type that is mentioned.
http://www.tpub.com/neets/book7/24k.htm
http://www.ehow.com/how_7679008_identify-diode-markings.html
There looks to be others on the board that are identical. Take it to an electronics supply place and ask. Radio shack may do in a pinch if you find someone who has knowledge beyond cell phones and magic jack.
Please do post up your results, win or lose.
Thanks for the resource links. I'm getting help from some electronics-savvy folks. I'll post my results. A PO replaced the 5A inline fuse with a 15A one and it was blown. Whatever is damaged on my board from the excessive current is likely the problem with other boards. I'm wondering if it would just be better to etch a new PCB with a modern relay/controller on it and relocate the connector to the new one to have a drop-in replacement. We'll see.
I think that might be the fuse for the amnmeter.. The relay is right under the dash connected to the control module.
Curtice
SILVER Star
Thanks. I was thinking my ammeter fuse is right below that one I am pointing to, unless I am way off. You can see it in the black casing at the bottom of the photo (it has 2 fuses to protect for fusible link, correct...?). Or am I mistaken?
I did just find this (begin at post #11): https://forum.ih8mud.com/40-55-series-tech/698049-fusible-link-fuses-issue.html.
So you are probably right that this isn't what I thought it was. I thought I was on the right track because the wire color (blue w/red stripe) was the same as the one to the fan. In the pic on that post, the wire is white w/blue stripe.
I guess I will keep looking for the fuse under the dash. 20 minutes of poking around yesterday and I couldn't find it.
