Cooling fan not functioning properly. STOP light on

[allypally]

My 406 HDI 90 temp gauge sometimes goes down to zero and sometime fluctuates. Occasionally especially on hot days or stuck in traffic the red Stop light starts to flash coinciding with gauge problems, it seems worse when car is hot. Car is not overheating. Fan comes on at high speed when i disconnect sender switch. On checking relays and resisters i found the Grey resister to be open circuit. I have now changed grey resister and temp sender switch. I suspect the Red stop light was coming on because the low speed fan was not working or detecting incorrect temp reading. How can i tell if i have fixed the problem. The low speed fan does not come on when i select A/C but my A/C does not work as it keeps losing pressure. Should it still come on? Anyone got any experience of this or will i just have to wait until car gets hot enough to see if low speed cuts in.

[allypally]

Cooling fans now working normally so i suspect it was the cooling fan resister(grey one) that was faulty as i know this was open circuit. I did change the temp gauge sender unit as well so it could have been this as well.