W140 s500 coolant 4pin sensor connect way - 500-Class Mercedes-Benz Cars & Trucks

not normally it should be a couple of clips see this thread
http://www.benzworld.org/forums/w140-s-class/1585708-diy-replace-front-right-speed-sensor.html
seaming there is 1 per side

im sure the timing cover at front of the engine
http://www.importecwarehouse.com/Mercedes-Cam-Camshaft-Position-Sensor-Front-of-Eng-p/mb0021539528.htm

here is a web site that shows how to fix it it is to long to post all the repair procedure. http://www.benzworld.org/forums/w140-s-class/1512673-diy-p0715-p0720-speed-sensor-contact.html

COOLANT TEMPERATURE SENSOR THREADS INTO A COOLANT PIPE NEAR THE COOLANT OUTLET.LOOK AT SMALL COOLANT PIPES AT RADIATOR.YOU WILL SEE A SENSOR WITH WIRES CONNECTING TO IT.WITH COOLANT COOLANT HOSES CONNECTED TO IT.COOLANT TEMPERATURE SENSOR IS BETWEEN TWO COOLANT HOSES CANT MISS IT.YOU HAVE TO SQUEEZE CLAPS ON HOSES WITH PLIERS IN ORDER TO REMOVE HOSES FROM COOLANT SENSOR.

YOU NEED A TUNE UP IF IT HAS BEEN A WHILE SINCE REPLACE SPARK PLUGS AND CHANGE FUEL FILTER + CHANGE AIR FILTER INJECTORS NEED CLEANING.IF ALL IS GOOD.OTHER POSSIBLE CAUSES CAR NOT TO START COULD BE FAULTY COOLANT TEMPERATURE SENSOR OR CRANKSHAFT POSITION SENSOR YOU NEED A SCANNER TO HAVE THOSE CHECK.THAT WILL SAVE YOU TIME AND MONEY.

what you want is a customizing shop, start by getting some custom car magazines and look for an shop in your city in the ads page

4.2L Engine To Remove:

1. Disconnect the negative battery cable from the battery.
2. Drain the coolant from the engine.
3. Disconnect the engine coolant temperature (ECT) sensor connector. Engine coolant temperature sensor removal and installation
   
   
4. Remove the engine coolant temperature (ECT) sensor from the engine.

To Install:

1. Apply thread sealer P/N 12346004 or equivalent to the engine coolant temperature (ECT) sensor threads.
2. Install the engine coolant temperature (ECT) sensor into the engine. Torque the sensor to 12 ft-lb (16 Nm).
3. Connect the engine coolant temperature (ECT) sensor connector.
4. Refill the engine with coolant.
5. Connect the negative battery cable to the battery.

5.3L & 6.0L Engines To Remove:

1. Drain the coolant from the engine.
2. Disconnect the engine coolant temperature (ECT) sensor connector. Engine coolant temperature sensor removal and installation
   
   
3. Remove the engine coolant temperature (ECT) sensor from the left cylinder head.

To Install:

1. Apply thread sealer P/N 12346004 or equivalent to the engine coolant temperature (ECT) sensor threads.
2. Install the engine coolant temperature (ECT) sensor into the left cylinder head. Torque the sensor to 15 ft-lb (20 Nm).
3. Connect the engine coolant temperature (ECT) sensor connector.
4. Refill the engine with coolant.

Your compressor clutch is not engaged that was why AC is not on. The clutch is controlled by several sensors: coolant temp, refrigerant pressure, compressor speed sensor, evaporator temp sensor... First to make sure your Clutch is working then start tracing back to these other sensors. Look at the compressor, there is a plug of electrical wire on it. One prong is for speed sensor feedback, the others are for power connectors to turn on the clutch. Jump wires to power to clutch to check if it is working. That is just the beginning of AC troubleshooting. Good luck.

this is the best diagram I have ever seen for the plug wire routing