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post #1 of (permalink) Old 06-24-2019, 02:45 PM Thread Starter
BenzWorld Member
Date registered: May 2019
Vehicle: 1994 s600 coupe
Posts: 121
Mentioned: 0 Post(s)
Quoted: 19 Post(s)
(Thread Starter)
v12 engine 4 coolant temperature senders

there is a total of (4) coolant temperature sensors on the front water crossover of V12,
on my 1994 W140 coupe.
2 are identical, one on each side, and have 4 pins in each sensor
2 are in the middle of the engine, one has a single pin connector, the other has a 2 pin connector
I unplugged and cleaned all of them, all were somewhat corroded, the single pin connector was pretty bad. could barely unplug the single pin. had to spray it with PB blaster to get it off.
question- what do each of them do ?
I'm assuming they control the temperature gauge inside the car, and ground the o2 sensor circuits to put the engine in closed loop when it warms up, and also 1 or 2 may control the dual fans. what else ?
2nd question, which ones do what ?
now the big question, you can plug the 4 pin connector in 4 different ways. there's no guides on it. does it matter which way the plug goes into the 4 pins in the sensor ? just wondering why they would make a sensor that doesn't have guides so it only goes in one position. I'm leaving it how it was when I got it, but would like to know if there's a right or wrong way to plug it in.
any help appreciated, thanks- regards
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