C4 fans by steering column keep burning

[AstaFire]

Hi all, the wires for the fans by the steering column on my c4 grand picasso (2008 reg, 2.0HDi, DW10QBTED4 RHJ engine code) keep burning out, i have changed the relay in the engine bay, put new fans in, but It still keeps burning out. Does anyone have a wiring diagram or any idea what's causing it to keep burning out?
Thanks in advance

[xantia_v6]

Most likely the fan motor is drawing too much current. This may be due to stiff bearings, or it may be an internal short in the motor.

[PaulC5]

Is the pollen filter blocked up, when was it last changed. Might also be a short in the wiring but I would expect a fuse to blow, unless one has been replaced with a high amp one.

[GiveMeABreak]

^^ Both these suggestions - check when the pollen filter was last changed - you'd be surprised how much crud and bugs can get in there and this restrict the air flow, so can put a strain on the blower motor.