Kia ceed 1.6 CRDI start up problems rough idle cold starts, read description glow plugs issues,

Hello guys, we had problem with our KIA ceed 1.6 CRDI 85kw, problems started when it was under 5°C/41Fahrenheit, car was cranking for 10 seconds and then started with blue smoke and rough idle, when it was -5°C/23Fahrenheit car wa only cranking no start at all, so we found that 3 glow plugs were not working I changed them but issues remains. Then I checked main glow plug relay was burnt, so I changed it and car is starting like a hell .

[KlutchBelgium]

Hello,
I have same problem with moving idle 3 or 4 seconds with blue smoke (1.6 crdi 115)
It's the big relay (80A 32v?)

[hellomynameisbilal]

So why it does this? Is it relay problem because i have same issue