What are these plugs?

[Smerff]

I just hot this 2010 Citroen Relay, it was running like a bag of scrap metal. I replaced all injectors and now it runs mint. I am doing fluid changes and see the fuel filter is modified and has 3 plugs that I'm not sure what they do. I have check engine light on so maybe somethings are unplugged. Any ideas? Thanks in advance

[wheeler]

The one on the top of the filter most likely a fuel heater
The one on the bottom most likely a water in fuel sensor
not sure about the black one

[Smerff]

Thanks for replying. Should these have plugs to plug in or does the filter look like it's from another vehicle?

[Hell Razor5543]

It may also be possible that (on your vehicle) those plugs are unused. Manufacturers won't have a different wiring loom for each model in their range for cost reasons, and those plugs might be for a model with a higher specification than yours.

[wurlycorner]

They might even be from a replacement fuel filter housing that was intended for a different market (eg for a vehicle sold in the Nordic circle v. one sold into the UK)