Help! Blow by heater problem.

[JaneKillips]

Hi I have a motorhome here based on Fiat and it is quite new only done 5000 miles. And yellow engine warning light came on and I had to take it to the dealer who then charged me 140 quid to turn the light off and tell me that it's a blow by heater fault. Now the light has come straight back on again and I am supposed supposed to be going on holiday on Thursday with this van. I have looked at the Internet and it says the blue by heater is only needed in cold weather? I can't get into the garage before I am supposed to go do you think it's safe to drive or not?
Help please! Appreciate any answers thanks