405 cooling fans switching on - flattening battery

My daughter's 1989 405 the cooling fans occasionally remain on after stopping
and turniong off the ignition. The car isn't overheated, the water level is
OK.

The problem with trying to locate the problem is that the Haynes manuals just
don't cover this car's electrics at all.

I'd appreciate any suggestions of where to start l;ooking for the reason for
the fans staying on.

I assume the fans are on because some sensor thinks the engine is hot - or
there is a bad connection to some sensor.

Urgent assistance would be appreciated as she is home for the weekend from
another city 200km away where she is attending university (naturally she's
poverty stricken and can't pay a Peugeot mechnaic to look for the problem).

Regards

Ron

 

I had another look - it could be a sticky relay.

Ron

 

I had this problem with the interior fans staying on and flattening my
battery overnight.

I needed a new battery anyway, and when I changed that the problem
disappeared.

 

sorry, in a 1994 306

 

Some 405's have this feature as standard. The fan runs on for 12 minutes,
then stops. Don't worry about it. Its a French car and they do things in a
different way.

If the battery is ok then you should not have any problems with this.

 

Yep, I had an old 309 used to start the fan as I was walking away.
Frightened the be-jaysus out of me first time I heard it.
It never ran for long or bothered a decent battery.
Rick.

 

Ahh. I wondered about that as my Range Rover does the same thing if the
engine is hot.

However, in this case the 405 wouldn't switch off and it did flatten the
battery.

I've now found the wiring diagram sent to me last year by Mr. Nice (Haynes
didn't put the cooling fan wiring diagrams in the petrol workshop manual, just
the diesel workshop manual) and I've raced the wiring out into a readable form
(pity Haynes didn't) and it appears that the fans shouldn't run unless the
ignition is switched on. Of course that does assume the diagrams are
correct - always a worry with Haynes.

I suspect a sticking fan relay (the LH one - looking from the driver's seat -
of the three behind the grille) but as I can't get the fault to recur (it did
yesterday and that's when I did my faultfinding) I can't be certain I've fixed
it.

All the best

Ron