Identifying Temperature Sensors/Switches? (1 Viewer)

[mike1305]

Probably a dumb question, but for the life of me, I can't seem to figure out what all these different sensors do.

Toyota Auto Parts By Model and Year - Toyota Pickup Parts - 1982-Toyota-Pickup - Electrical, Charging, Starting and Engine - YOTASHOP

www.yotashop.com

I presume the second one with the spade connector is for the dash gauge. What are the other two for? I have an '82 Pickup with 22R motor. Also has factory AC. Here's what I see installed after all my desmog handiwork. The truck runs fine btw. It does seem to take a solid 15-20m to get warmed up, could be something I did with one of these sensors or maybe the t-stat is stuck open, but I just want to know for my own sake, and perhaps refresh some 40 year old parts and redo some of my jank wiring.

On the left (front of block) is the sender for the gauge. on the right (rear) appears to be the "Coolant Temperature Sensor" listed on the right on the webpage. My guesses would be that it controls the radiator fan? The wire just ducks into the harness and I can't tell where it goes. That $152 switch is still a total mystery to me.

Finally, do you think I have them installed in the right spots? Would the plug facing sideways below the thermostat neck be a better spot for either of these things?

 

[pappy]

From left to right. I have no idea what they do on a 22R, but on a 22RE ...

1. Temperature switch, located on top of the thermostat housing on early 22re engines. It turns off the AC if the engine gets too hot.

2. Gauge sender. Located between runners #2 and #3 on the intake manifold.

3. EFI thermo sensor. It talks to the engine computer. Located at the front of the engine next to the cold start time switch (brown).

 

[pappy]

The truck runs fine btw. It does seem to take a solid 15-20m to get warmed up, could be something I did with one of these sensors or maybe the t-stat is stuck open, but I just want to know for my own sake, and perhaps refresh some 40 year old parts and redo some of my jank wiring.

Did you by chance delete the hot air intake system during your desmog?

"This system leads a hot air supply to the carburetor in cold weather to improve driveability and to prevent the carburetor from icing in extremely cold weather."

 

[mike1305]

From left to right. I have no idea what they do on a 22R, but on a 22RE ...

1. Temperature switch, located on top of the thermostat housing on early 22re engines. It turns off the AC if the engine gets too hot.

2. Gauge sender. Located between runners #2 and #3 on the intake manifold.

3. EFI thermo sensor. It talks to the engine computer. Located at the front of the engine next to the cold start time switch (brown).

Why thankyouverymuch! Assuming that #3 is completely irrelevant for me since I'm carbureted. #1 is an interesting one... I don't run the AC often here in Colorado, but it seems reasonable that I could just turn it off manually if I see temps creeping up. Crazy that it's $150 lmao. I don't even know if mine works, guess I would have to go sit in a parking lot on a hot day with the A/C cranked and see what happens. Or yank it out and find a FSM with a test procedure. But it certainly explains it. For some reason, I recalled it being related to turning the fan on/off. I presume that's controlled within the water pump, since it can sense temps right there, yeah?

 

[mike1305]

Did you by chance delete the hot air intake system during your desmog?

"This system leads a hot air supply to the carburetor in cold weather to improve driveability and to prevent the carburetor from icing in extremely cold weather."

View attachment 3018711

Why yes I certainly did! Went with a Weber 36/32, new intake and exhaust manifolds so the system was homeless so to speak. Google hasn't been helpful in telling me what a normal warmup time would be. I let it idle for 2-3m then drove it 20m to Lowes yesterday and it got to temp right as I got there (about 65F out). Figured with a tiny little aluminum block it would warm up quicker, but not having the HAI certainly doesn't help my case. I have a new t-stat on the way since it seemed like a worthwhile $30 of preventative maintenance.