Vauxhall is to write to 220,000 Zafira B owners after more than 130 of the models were reported to have burst into flames.
Rory Harvey, the company's chairman and managing director, said 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, and a thorough investigation is under way.
"In addition it should be noted that if you are the first owner of your Zafira B and your heating and ventilation system is functioning well and your car has never been subject to any repair in this area, there should be no risk of a fire starting," he said.
In a video broadcast on YouTube, Mr Harvey said the company would be writing directly to all relevant Zafira B owners, using name and address data provided by the DVLA - numbering some 220,000 in total.
The letter will 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.
The letters will be distributed in a staged process from November 12.
"We fully understand the seriousness of the situation and your personal concerns about safety," he added.
"And please be assured that we will not rest until we are fully confident that we have resolved this issue."
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