recently l bought a 2nd hand 1999 T reg peugeot 306 meridian only trouble is .... when l start the car the fan comes on straight away not the main fan (to say its over heating) but another one, obviously beinwoman l have no idea what it is, no white gunk oil looks fine, any ideas what this could be? many thanks x

l would not worry to much about it. l had a car come in the shop that did the same thing, the previous mechanic had hard wired the fan to cool the engine because of over heating problems. If your talking about the interior fan your car is definently possesed and you should take it to your nearest priest

The cooling fan can come on at 2 or 3 different speeds. When you say the main fan for overheating l think you are refering to the cooling fan on fast speed. If your car has air conditioning (which l suspect it has) then the cooling fans will come on at slow speed whenever the engine is running AND the air conditioning is switched on. Turn the air con off and after a few moments the fans will stop.

Short answer - French Electrics!!!!!

More specifically, l have found that often electrical issues r related to poor connections within the wiring, connectors & wire terminals, & in particular earthing points, rather than actual faults.

With the air conditioning off ie in Eco mode, the fans should run in one of three modes. when the car is cold, the fans should both be off. when it warms up, both fans should turn on to slow speed for a while to cool down the radiator. If it was really hot, or if u blocked the air to the radiator, both fans should eventually turn on to high speed (quite noisy).

It may help if u get a Haynes workshop manual for the wiring diagrammes, but a few things to check are:
1. fuses - there should be couple of 30 amp fuses in the engine bay for the fans.
2. relays - there should be a couple of relays near the fans that control their operation
3. previous modification - look for non standard wires, particularly near the fans or the sensors on the engine. Someone may have added a wire that causes the fan to run all the time the engine is.
4. Check the other fan does actually run.

For all these, check the iten (fuse or relay etc) as well as the condition of the terminals & wires which plug into it.