Glow Plug Relay on 2003 Volkswagen Jetta TDI

I check engine light is on it states that is it Glow Plug Relay # 3. What is the cost of replacing this and what harm could this do to the engine

Asked by for the 2003 Volkswagen Jetta TDI
How much will I expect the machinic to charge?
1 more answer
The plugs are approx $19.99 a piece. You can change the one that is bad or all of them. I would recommend having them ohm tested first. If they all ohm out at .9 then it is your harness that needs to be replaced.