Having trouble getting replacement plugs to work on your Grand Cherokee CRD? You probably were sold the wrong plugs. Even though it shares the same engine, the Grand Cherokee CRD uses a different plug than the Mercedes models.
The only plugs that will work on the Grand Cherokee CRD are 4.4V plugs made by BERU. There are NO BOSCH PLUGS that will work. If a store tries to tell you that the Bosch will work, THEY ARE WRONG, THEY DO NOT WORK. Bosch only makes a 7V plug and this will cause starting issues and glow plug faults.