fan on all the time!

[51steve]

Hello Everyone,

Well the 4L ( Wall-E -son named him) has been put through it's paces. Two round trips to Paris and no real problems! However, now that I'm down in the Dordogne, Wall-E has developed a small problem- the fan starts running immediately upon starting, even when the engine is stone cold in the morning! Is this a symptom of a broken fan switch? If so, does the switch come with a gasket or do I use a sealant, and which type of sealant?

Thanks to all,

Steve

 

[malcolm]

Could be the fan switch, but they normally fail the other way so the fan never comes on at all. It's worth checking out the wiring to make sure nobody has bypassed the switch. That's a common "fix" for when the cooling system isn't holding pressure but not a fix that actually works.

If it is the switch then it has a fibre washer for sealing. It probably won't come with the switch. The old one might be OK, otherwise you should be able to order one at the same time as the switch.

 

[51steve]

Thanks Malcom,

The switch doesn't seem to be bypassed. Or at least it doesn't seem to be. There is a wire from the harness that goes to the bottom of the fan switch then there is a wire that goes from the top of the fan switch to the fan. How do I check if the fan switch is faulty while it is still in place in the radiator? Or since it is a cheap part should I just swap the switch out with a new one and see if that solves the problem?

Steve

 

[malcolm]

To test the switch when it's cold just remove the wires and measure resistance across the switch - if it's closed contact when cold it's broken.

 

[Pavel]

Hi Steve, you start the could engine and the fan turns. Than you can disconnect the wires on the fan switch. If the fan turns nevertheless, there is a short circuit in the wires.

 

[51steve]

Hello Malcolm,

I plead ignorance when it comes to using a multimeter to check resistance. However I've used a multimeter to check voltage and amperage. Should I assume that I put the meter on Ohms, attach the leads across the switch and if the switch is stuck, as you say in the "closed contact" position I should get a reading of zero, meaning that electricity is flowing across the contacts?

Thanks for the help!

Steve

 

[malcolm]

Exactly. Need to be careful that everything is disconnected and switched off - the ohm setting can go pop if exposed to any electricity.

 

[51steve]

WOO HOO,

Off I go to buy a French multimeter. Get back with you in a few days.

Steve

 

[mr-reno-139]

hi steve
think pavels idea is simpler simply unplug fan switch then switch ignition on see what happens if the fan then stays off it can only be stuck switch - rare but not unheard of

think a new switch will be cheaper than a french multimeter that will then tell you that you need a new switch any way

funny had same problem yesterday with clio diesel except it was relay jammed in the on position (even rarer - dont worry there isnt a relay fitted as standard on R4 but you never know maybe someone has modded wiring and fitted one :eek

 

[BatW]

Had a boil up at the weekend when sat in traffic for an age.

If I've got to drain the coolant down to test the fan switch I'm going to buy a new one in advance; before I start ringing around, is this a dealer only part?

Cheers

 

[bantamallan]

Local factor should be able to supply or check out e-bay .