How to determine which is pin 1?
 

A 400e just got a new upper wiring harness.

The replacement was without major event except for one connector that crumbled when it was pulled. Due to the mishap I don’t know which side pin 1 is on.

Can anyone help? The connector in question is the one with the red circle around it in the attached image.

In addition what is the circled sensor used for? There was 0 insulation on the wires connecting to this, and I would not be surprised if the wires were shorted together for a long time. That makes me think that perhaps the device could be dead, but I dunno.

!!!Thanks!!!

Looks like that's a temp sensor? It's likely that it doesn't matter how it is connected.

-J

Several wrote that this sensor does not have a pin 1. Some added that if the connector is disconnected from the sensor, with the ignition key in the “on” position, that should make the aux fans turn. In the case of the aux fans in this particular car, the test failed and the aux fans did not turn. That’s not a primary concern at the moment, and becomes an issue for another day.

I believe your 400E has the same fan control strategy as my 350SDL... sometimes pulling the plug off starts the fans, sometimes it does not. Sometimes the engine has to be somewhat warm first. If you short the 2 pins together the fans should always come on.

-J