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[Sir Tigger KC]

Hi, There are two switchs on the radiator on the near side, one at the top and one at the bottom.  I'm not sure what they do    Is the top one the fan switch and the bottom one the temp sender unit??

Many Thanks

[ScaniaV8]

I believe the top one  is the primary thermo switch controlling operation of all fans on low speed at 212degF (all fans being 3 in total , 2 auxilliary at front and 1 main radiator fan cooling in front of engine, assuming you have A/C fitted).
The bottom one is the secondary thermo control switch which kicks in the secondary auxillairy fan at high speed when 221degF is reached.
The switches and fans are also controlled by relays in the engine fuse box.
At 230degF the top thermo switch and relays cuts both the Aux fans to low speed and sets the Main radiator cooling fan into high speed.

Hope this helps 

[Sir Tigger KC]

Thanks Scania!

I'm putting a new rad in and am wondering if its worth putting new switchs on as well as they're not that expensive.  Do they tend to fail?

Cheers

[ScaniaV8]

I believe they are quite reliable but I suppose if poor maintenance of coolant changes and Radiator clogging then I suppose they will not perform correctly.
As you say they are relatively cheap  (circa £16.00) in the scale of pricing so maybe refit new ones with the new Radiator. It's worth checking all switch plugs are connected properly as I have heard of VX dealers sometimes forgetting to re-connect properly after servicing activity, particularly the main fan unit plug/switch.,leading to potential overheating
good luck with the new Rad fitting.

[Sir Tigger KC]

Thanks again Scania.  Yes, it seems daft not to put new switchs on a new rad while it's all in peices.....

I've seen them on fleabay and I can tackle the camcover gaskets while I'm waiting 

Cheers