[blankenshipac]

The clips on my e90 335i front air vents broke. Bought replacement on eBay. Took apart the front trim to replace with the new air vent part and in the process unplugged the start stop button. Finally finished and when I went to start the car back up, no crank or anything. The car won’t start. Car was running perfectly before and I double checked to make sure I plugged everything back in. Any help??

[RockCrusher]

No crank could be due to a bad battery.

But if you disconnected/connected connections of the electrical system without disconnecting the battery first you might have glitched the car's electronics.

If not a fatal glitch a proper disconnect of the battery -- to dissipate all residual electrical power in the car's electrical system -- then a reconnect of the battery can be the cure.

With an older car disconnecting/connecting connectors can have a pin/socket get damaged and not all connections in the socket are good. Double check the start/stop button connections are good.

Separate the connectors and use a good flash light to check all the pins are present and accounted for and all the pin sockets look ok.