the 4 pin one is for EZL- CIS etc, the single pin on the water pump housing would be for shift softening, the three prong is for the A/C cutout and high speed fan kick on, the temp needle sender would be about in the middle of the head or near the firewall.

Usually MB engines have 3 sensors. Some have 4 for shift softening.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)