‘78 Carb cooling fan relay (1 Viewer)

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Update 8:53pm fan still running..........clearly longer than it should at 1.5 hours. Going to disconnect it
Something's not right - it should run maybe 20-30 min max then time out
 
I agree, when mine was running it never ran for more than 10-12 minutes, ever.
 
Something's not right - it should run maybe 20-30 min max then time out
That's approx what the original one did, when it did kick on.

So I just disconnected the battery, the relay clicked and shut off. I'll be troubleshooting it for the next few days in between work....
 
That's approx what the original one did, when it did kick on.

So I just disconnected the battery, the relay clicked and shut off. I'll be troubleshooting it for the next few days in between work....
Maybe @ToyotaMatt has a solution. Even when crazy hot it never ran too long.
 
I’ve sunk around $50 into new relay/control box/temp sensor...... still not functioning off the temp sensor! Mine runs approx 30 minutes after shutdown when grounded, which isn’t bad but I’m gonna install a toggle switch to disable when I want (got an existing PO dash hole anyway 😉)
 
I’ve sunk around $50 into new relay/control box/temp sensor...... still not functioning off the temp sensor! Mine runs approx 30 minutes after shutdown when grounded, which isn’t bad but I’m gonna install a toggle switch to disable when I want (got an existing PO dash hole anyway 😉)
Huh..... I’ve already said this earlier in this thread! Age and a dash a Woodford/rocks 🥃 will do this! 🤣
 
I’ve sunk around $50 into new relay/control box/temp sensor...... still not functioning off the temp sensor! Mine runs approx 30 minutes after shutdown when grounded, which isn’t bad but I’m gonna install a toggle switch to disable when I want (got an existing PO dash hole anyway 😉)


If your relay and timer are working properly after you momentarily ground the wire for the sensor, then your only problem is in the sensor. These use a snap switch. It is either on or off. They are cheap and available on Amazon. Just get a 160 or 175 degree snap switch, mount it so it's case is grounded, allow the very tip of the switch to lightly touch the intake manifold near the carb, connect the single wire to it and you are good to go.
 
If your relay and timer are working properly after you momentarily ground the wire for the sensor, then your only problem is in the sensor. These use a snap switch. It is either on or off. They are cheap and available on Amazon. Just get a 160 or 175 degree snap switch, mount it so it's case is grounded, allow the very tip of the switch to lightly touch the intake manifold near the carb, connect the single wire to it and you are good to go.

Thinking the same myself..... the Toyota temp sensor is rather hard to source but I did get one off of a parts rig for $30 to replace mine
It may be shot as well! :cheers:
 
If your relay and timer are working properly after you momentarily ground the wire for the sensor, then your only problem is in the sensor. These use a snap switch. It is either on or off. They are cheap and available on Amazon. Just get a 160 or 175 degree snap switch, mount it so it's case is grounded, allow the very tip of the switch to lightly touch the intake manifold near the carb, connect the single wire to it and you are good to go.
Grounding did nothing. Not sure on relay. Thanks.
 
Will try grounding once more. Where is best place to ground? Thanks.
 
Something like this?

16DB56E5-4F95-479D-A2CE-C1806FE7682B.png
16DB56E5-4F95-479D-A2CE-C1806FE7682B.png
 
I used this one from Amazon. Amazon product ASIN B01E52N7OO I think I used the 165 degree On and 145 degree Off switch. Made a bracket that mounted on the two holes that already existed in the intake, drilled a hole in it and threaded the hole to accept the threads on the snap switch. You can discard the larger threaded adapter that comes with the switch. Run the switch into the bracket until the end of the switch touches the intake manifold near the carburetor. If your original mount for the snap switch is still there, use yours. Mine was gone.
 
Inline fuse also replaced even thought it looked just fine 🙄. Opinions? Thanks guys.
In my '79 Mitsubishi truck that I owned, I had an issue with a glass fuse. It LOOKED fine so I was looking farther up the electrical chain for the issue. The fuse had opened at the end where you could not see the break. Drove me nuts for a while. Bottom line is ALWAYS use VOM to check the integrity of the fuse.
If the circuit is energized, read across the fuse with the VOM setting on volts, if you get a reading that is ~12 volts on a 12 volt system bad fuse.
If the fuse is pulled out of the circuit, set the VOM to Ohms, reading should be zero for a good fuse.
Make sure that the fixture that the fuse sits into is not corroded.
 

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