fj40 carb cooling fan...do you run yours? (1 Viewer)

[tls3601]

Replacing the inline 5A fuse worked last time but no workie now. I have another relay box so time for a wiggle test on the connector and try new box.

 

[tomcrusr]

Replacing the inline 5A fuse worked last time but no workie now. I have another relay box so time for a wiggle test on the connector and try new box.

Let us know how it turns out. I'll need to know what to do next time
-Tom

 

[mrldcty]

Yes. That will not work. The relay is smarter than that. It has more electronics on it than just about anything I've seen on this rig. Apparently expects to see a slow reduction in resistance and a slow increase in resistance- all from the thermocouple.

Is it true that the controller needs to see a gradual resistance change before it will power the fan, thus, grounding the sensor connection isn't a foolproof test of the sensor?

I'm trouble shooting my fan, which has not run AFAIK since I bought my mostly stock 1/80 FJ40 back in July.

- The fan runs when jumped directly to battery,
- the fuse next to controller is in tact,
- the fan doesn't run when I cycle the ignition on/off with the thermister connection grounded (to the battery).

Does that actually indicate the controller or relay is the issue or might it still be the temp sensor?

 

[fjc-man]

If you haven’t sifted through this entire thread, I would recommend looking at the pictures in post #302 of the circuit board. When people mention resoldering the board they are referring to the back side of the plug pins. I’d suggest all of those pins be resoldered, even if you don’t see cracking of the joint.

 

[mrldcty]

If you haven’t sifted through this entire thread, I would recommend looking at the pictures in post #302 of the circuit board. When people mention resoldering the board they are referring to the back side of the plug pins. I’d suggest all of those pins be resoldered, even if you don’t see cracking of the joint.

Thanks, will do... so I gather that means you think grounding the sensor connection should prove it's something other than the sensor, i.e., no gradual resistance "memory" needed?

 

[fjc-man]

I’m just saying that any one of those solder joints, including the one for thermo sensor could be the problem. The control unit itself may be just fine if the connections are good.

 

[mrldcty]

I just saying that any one of those solder joints, including the one for thermo sensor could be the problem. The control unit itself may be just fine if the connections are good.

Ah... gotcha... thanks for that!

 

[fjc-man]

I forgot to add the picture.

 

[unixman]

Is it true that the controller needs to see a gradual resistance change before it will power the fan, thus, grounding the sensor connection isn't a foolproof test of the sensor?
Does that actually indicate the controller or relay is the issue or might it still be the temp sensor?

I don't believe the controller measures the rate of resistance change; it simply measures the resistance at any given time. The controller is a collection of analog components of which any can eventually fail. My board had ruined diodes after a previous owner replaced the 5A fuse with a 15A one. I tried replacing the diodes but with no success. I eventually bought a replacement one and later created a digital replacement as a personal goal. You can read more than you wanted to know about Toyota's fan controller here: OEM Carb Fan Controller Replacement - https://forum.ih8mud.com/threads/oem-carb-fan-controller-replacement.877001/

 

[mrldcty]

I don't believe the controller measures the rate of resistance change; it simply measures the resistance at any given time. The controller is a collection of analog components of which any can eventually fail. My board had ruined diodes after a previous owner replaced the 5A fuse with a 15A one. I tried replacing the diodes but with no success. I eventually bought a replacement one and later created a digital replacement as a personal goal. You can read more than you wanted to know about Toyota's fan controller here: OEM Carb Fan Controller Replacement - https://forum.ih8mud.com/threads/oem-carb-fan-controller-replacement.877001/

Very cool unixman! (pun intended)... I have another controller on the way. If it doesn't work, I will crack it and see if I can fix it or the one on the truck. After that... I might have to pick up your design and try to replicate. I also have a data system out of my old race car that I have been looking for an excuse to use.

 

[mattressking]

Bringing this one back to life. Working through my carb fan relay and I’ve found the smaller relay clicks when testing per FSM, however the larger relay is not activating. Manually moving the relay contact over gets the test bulb to illuminate without input from key (pin 4 in diagram).

Any one dealt with the relay not clicking and had a solution? I don’t see any failures on the board and have reflowed every cold joint I can see. Could’ve missed one but no luck, currently retracing the circuits.

What appears to be a leaking capacitor concerns me but it seems as though it’s common - has anyone replaced the cap and activated the larger relay?

 

[fjc-man]

You might try @Engineer8000 . He repairs these. Probably has a few for sale.

 

[TheHardWay]

How about a close up of the capacitor, especially the puddle of either glue or cap leakage.

 

[mattressking]

How about a close up of the capacitor, especially the puddle of either glue or cap leakage.

Here ya go, iPhone doesn’t do super well with extreme close up. Both sides shown

Ordered a spare from classic cruiser to use as a comparison and so I can hopefully get the fan working for now and sort this with my spare.

 

[Engineer8000]

That looks like a 60020 for a '78. Every one of those I've touched was non functional which is odd because the Denso modules are usually pretty reliable. I have several of those that have been electronically repaired/refurbished and fully tested.

 

[Engineer8000]

If you have one you would like to send in for repair or as a core for a known, tested functional controller, let me know. I am pretty reasonable.

 

[Goldbug]

Assembled Carb Fan Experts:
I'm trying to get mine working. I have a '78 that was desmogged by a PO. I have a lot of trouble starting it in the summer if I run into the store quickly or similar, so thinking a working fan would help. I read through this thread and others, and did some spelunking last night to see what I've got. I know the fan works if hooked up to a charge directly. I believe that I'm missing the connection between the fan and the thermostat? that's on the manifold. Is that correct and if so, any suggestions on options for a fix? I assume it's not a simple as run a wire between that and the fan. I expect I may also need to do some work on the circuit board or source a repaired one.

thank you. electronics aren't my strong suit. yet.

 

[mattressking]

Assembled Carb Fan Experts:
I'm trying to get mine working. I have a '78 that was desmogged by a PO. I have a lot of trouble starting it in the summer if I run into the store quickly or similar, so thinking a working fan would help. I read through this thread and others, and did some spelunking last night to see what I've got. I know the fan works if hooked up to a charge directly. I believe that I'm missing the connection between the fan and the thermostat? that's on the manifold. Is that correct and if so, any suggestions on options for a fix? I assume it's not a simple as run a wire between that and the fan. I expect I may also need to do some work on the circuit board or source a repaired one.

thank you. electronics aren't my strong suit. yet.

View attachment 3536083

View attachment 3536084

I don't see the ground switch wire to your sensor. Sensor isn't required, it is only to provide temperature resistance to ground switch wire to unit.

Locate the ground wire (Blue/Black or Solid Blue) off harness on driver fender (single wire, would be in combination with fuel cut solenoid, brake fluid level sensor harness) then ground to chassis. Cycle ignition switch on/off and fan *should* turn on. If it doesn't, you need to test fan and fuses then lastly fan controller.

 

[greenEFSI]

I don't see the ground switch wire to your sensor. Sensor isn't required, it is only to provide temperature resistance to ground switch wire to unit.

Locate the ground wire (Blue/Black or Solid Blue) off harness on driver fender (single wire, would be in combination with fuel cut solenoid, brake fluid level sensor harness) then ground to chassis. Cycle ignition switch on/off and fan *should* turn on. If it doesn't, you need to test fan and fuses then lastly fan controller.

Do I leave that wire permanently grounded if I'm not running the sensor?

 

[mattressking]

Do I leave that wire permanently grounded if I'm not running the sensor?

Correct. Ground will run the fan after ignition shut off for ~20min