406 Rad cooling fans dead.

The radiator cooling fans have stopped working on my 97 406 petrol. I've
checked fuses and every connection I can find, but all ok. Any suggestions?
I fed up of cooking myself with the heater on full blast whilst stuck in
traffic!

Thanks
Chris

 

Firstly is 12V reaching the fans? If so is the ground connection ok. Can you
measure resistance across the motor. I don't know what the wattage of the
motors are but you should see a lowish resistance but not a dead short
obviously. Do the fans run if you put 12 V on them from a separate feed?

--
Malc

"AFB Mr Tracey."
"Underbirths are og"

Les Barker - Irrational Neutscene

 

Not sure about the earlier models, but the facelift models ('99 on) have a
box in front of the radiator containing several relays which control the
fan; the box catches a lot of water and it can get inside the box and
corrode the relays. You need to take off the front grill to access it.
Martin

 

Have you checked the thermostatic switch? I don't know specifically about
the 406, but it's usually screwed into the side of the radiator.

Withdraw the connector from the switch and bridge the contacts. Do the fans
now work?

Peter

 

That's worth knowing thanks


--
Malc

"AFB Mr Tracey."
"Underbirths are og"

Les Barker - Irrational Neutscene

 

Thanks to everyone for your suggestions. I've tried everything I can, but
failed. There is no 12 volts reaching the fans. With a battery connected
directly to them they run ok.

I can't find a thermostatic switch despite looking, although as you say
there must be one somewhere. A mechanic who has seen a similar problem told
me he had to have the ECU replaced - not an option I'd consider on a car
this old. Think I'll hard wire the fans to a BIG switch on the dash!

Cheers
Chris

 

Chris
I have a 1998 406 1.9TD with air con and had the same problem. This uses a
bitrol system to control the 2 fans. The system is switched on by the brown
thermostat of the three on the engine. This then switches a changeover
relay and 2 other relays to either give slow speed both fans in series or
fast both fans in parallel. Is this similar to your system, if so I can give
you the information to fault it.
Mike

 

Mike,
this is exactly what I am experiencing with my 1998 406 2.0. Cn you
provide me with the information I will require to fault it please.
Q-Ball

 

You have had a better response from the group than I did. If you look
at my recent post:
406SV - expensive 120k service
you will see I was puzzled why they replaced both fan motors (and,
according to the invoice, did not replace and sensors or relays). Both
motors seem to work OK. The vehicle had done 120k and I was not overly
concerned provided they fixed the problem.
And they did. There has been no sign of overheating since.
It may be that these motors, when aged, bind up during operation - that
is the only possibility I can think of for the fix having worked
(unless they replaced sensors/relays and forgot to charge - not likely!)

 

Chris
As both fan motors work either in series for slow speed or parallel for fast
speed. I assume their logic is replace both as if one has gone the other
will go shortly after as it is always operating when the other one is.
Having replaced one I understand this logic, as with my vehicle you need to
remove the radiator , intercooler and air con radiator to get at the fan
bolts.
Michael