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I'm mucking around under my manifold, educating myself on the engine and ran into these guys. Two cut wires, one on each side of the coolant bypass outlet/sensor cluster.
Solid blue on the right, solid Pink on the left. Each comes out of the sensor wire bundle, but it's inconclusive if they've been ripped out of a sensor. The car seems somewhat non-standard, and the FSM hasn't been all that helpful.
Here are my theories, please confirm or rebuke these (and any more info would be appreciated) :
I believe the pink wire might be a transmission temp sender wire that broke off from a cap, which is meant to fit that sensor right below.
The blue wire might be for a 4x4 auto temp sender but it's virtually impossible to find into on what that even does. Anyone know?
I've also heard reference to a sensor that cuts the A/C when the temps get too high. Is it one of these?
Finally, I have Overdrive on the AT. Could either of these be the OD temp sensor?
K, 99% sure the blue goes into the top of the blue sender cap and ripped off ages ago.
Follow up question: Suppose i confirm that a wire belongs somewhere, can I make my own connection with a spade connector directly to the sensor as a repair, or does the cap provide some other feature other than keeping dirt out?
you can confirm the color of the original wire to that connector by prying up the weather seal at the top. it’s rubber, and the wire passes through it. there should be enough of the wire under the seal to determine the color.
I'm mucking around under my manifold, educating myself on the engine and ran into these guys. Two cut wires, one on each side of the coolant bypass outlet/sensor cluster.
Solid blue on the right, solid Pink on the left. Each comes out of the sensor wire bundle, but it's inconclusive if they've been ripped out of a sensor. The car seems somewhat non-standard, and the FSM hasn't been all that helpful.
Here are my theories, please confirm or rebuke these (and any more info would be appreciated) :
I believe the pink wire might be a transmission temp sender wire that broke off from a cap, which is meant to fit that sensor right below.
The blue wire might be for a 4x4 auto temp sender but it's virtually impossible to find into on what that even does. Anyone know?
I've also heard reference to a sensor that cuts the A/C when the temps get too high. Is it one of these?
Finally, I have Overdrive on the AT. Could either of these be the OD temp sensor?
Thanks for taking a look!
Something looks off in this image, do you have three one wire sensors here (a third one off screen to the right)?
It's a safe bet the wires go to the sender or switch they are nearest. The factory didn't run them crisscrossing the water block.
Q&A
The transmission gets its temperature reading from the engine coolant temperature sensor (ECT signal, two wire sender).
The AC cut switch is a one wire connector, typically this has a rounded top with a male spade sticky out the top. On the 3vze some of these are a smaller size than the others. In some they are in the location of your blue plug, on others there are farther to the left on the block (right in your picture near that ground wire). This is the one I'm asking about being out of frame in the picture.
TSW, your mystery sensor is part of the fuel pressure regulator fuel pressure up circuit. When the engine is warm this triggers the FPU signal to switch the FPU VSV which disconnects the regulator from the intake vacuum and raises fuel pressure for warm starts.
...
TSW and AC cut. TSW is normally open, it closes at a certain temperature from memory this is something like 140. AC-cut is normally closed, it opens at a certain temperature which I don't recall some where in the 10-20 range above the thermostat.
@wallytoo - ripped open the 'rubber' cap (more like flint at this point) and confirmed the wire color. The plug on the right was connected to the blue wire as expected.
Yes, I have a one-wire sensor with an exposed spade sticking out. No cap. It's connected to the Orange(yellow?)/Blue wire you see sticking out right above the plenum bolt.
I made us a graphical aid. Ok, so here's what I THINK I have.
1. A/C cutoff switch? I've also seen it mentioned here that it might be the instrument cluster temperature sender unit. Can anyone confirm which? Thread here: https://www.yotatech.com/forums/f116...-gauge-224719/
2. ECT (engine coolant temperature sensor)
3. Coolant Temp SENDER unit *But what does it do/for what system?
4. CSI Time Switch
5. Coolant Temp SENDER unit *But what does it do/for what system? ***6. TVV exists, just off screen. And easy to ID
So close to tracking this down! Seems like the broken wires were both for Temp sender units, but I'd love to know what each of them do.
In the meantime, I've fixed the connections with spade connectors. We'll see if it does anything, but so far it doesn't seem to have any appreciable impact on the car's performance, at least at idle.
Nov 4, 2020 | 05:56 PM
thank you. 
