Vauxhall has begun writing to 220,000 Zafira B owners after almost 200 of the models were reported to have burst into flames.
The letters request that owners arrange to visit their local dealer for an inspection of the vehicle's heating and ventilation system, paid for by the company.
Rory Harvey, Vauxhall's chairman and managing director, said last week that evidence so far has shown the fires could be down to improper repair of the blower motor resistor and its thermal fuse, which is designed to protect the blower motor system.
But he added that he did not want to speculate on the root cause of the fires.
Denis Chick, director of communications at the manufacturer, told the Press Association that the letters are being sent out in a staged process to avoid dealers being overwhelmed.
"We're starting with the older vehicles because they are the most vulnerable," he said.
Mr Chick acknowledged that almost 200 fires have been reported on social media, but insisted that the manufacturer does not know if they are affected by the same issue.
"Whether they are fires due to this situation, nobody knows.
"The vast majority are fires that happened a while ago. The insurance companies have paid out and cars get scrapped," he said.
"We have only seen about 30 of our own. The fires have been so intense not even a forensic scientist could tell you how it started."
The company has insisted it will not rest until the issue is resolved.