What feeds the fan switch relay with power?

[Mathewrussell52]

I have seen it yes and I will try what you suggest but I don't think that's the cause. I don't see any logical connection to the suggested solution and the symptoms I'm having.

99-00 know for vapor lock with external fuel pump sounds like vapor lock to me.
This is newer but I’m sure part is same.

 

[philanthropy74]

can you tell me more about vapour lock? What is it? How is it cured and what symptoms?

 

[philanthropy74]

Okay, I think its the cylinder head coolant sensor but there aren't any on ebay. Anyone know where I can get one UK based?