Supplemental cabin heater fuse and relay location

If you have a Tip or Trick, some advice to give or you just want others to know something that is Specific to the a Diesel Citroen C3, please, post it here.
Forum rules
Tips for a Diesel powered Citroen C3

Tips from forum members are encouraged and very welcome.

Questions are not to be posted in this section

Think: Diesel engine, diesel fuel system, diesel injectors and glow plug tips
User avatar
My Name: Arfur Dent

Guru
Posts: 3417
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
Has thanked: 307 times
Been thanked: 119 times

Post

The Citroen C3 diesel models are equipped with a supplemental cabin heater that is activated by Engine ECU on a cold day, with a cold engine. This brings that cabin heat up to the requested level much more quickly than waiting for the engine to warm up.

The heavy currents are switched by hidden relays and the protection is by hidden maxi fuses.

If the supplemental cabin heater is not working, first check for 12v with ignition on at the wire on PIN 12 of 16 way green connector on BSM (CM15A). This wire feeds the hidden relays. If you have no power here, suspect the BSM. If you have power here, then move deeper to the hidden fuse box.


CM15A arrowed.
CM15A on PIN12 of 16way Green BSM connector - Citroen C3
CM15A on PIN12 of 16way Green BSM connector - Citroen C3

To access the hidden fuse box, disconnect and remove the battery, then the engine ECU. Remove the battery tray complete with the EPAS ECU. The battery tray is held by 2 bolts and then slides to the front bumper.

Under the headlight is a hidden relay and fuse box.

Citroen C3 supplemental cabin heater relay box
Citroen C3 supplemental cabin heater relay box
Citroen C3 hidden fuse box location for DIESEL models
Citroen C3 hidden fuse box location for DIESEL models


The relay box case can be removed to reveal the relay and fuse carrier board.

Inside the Citroen C3 hidden supplemental cabin heater relay box
Inside the Citroen C3 hidden supplemental cabin heater relay box

Standard 40A maxi fuses are inside

and the relays are standard automotive 5 pin relays (here)
You can add an avatar to your account - Avatar or change your vehicle details - Car Bio or even add a signature to your posts - Signature. But this is not all you can do in the User Control Panel :)
User avatar
My Name: Arfur Dent

Guru
Posts: 3417
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
Has thanked: 307 times
Been thanked: 119 times

Post

This hidden relay box had suffered water ingress in the past, damaging the relays and fuses :(

Corroded fuses
Corroded fuses


This is a water damaged relay (the upgraded version is waterproof)

Water damaged relay (bulging from corrosion)
Water damaged relay (bulging from corrosion)
You can add an avatar to your account - Avatar or change your vehicle details - Car Bio or even add a signature to your posts - Signature. But this is not all you can do in the User Control Panel :)
  • Similar Topics
    Replies
    Views
    Last post