Since February, GM has been encouraging dealers to form groups to pool money and buy local advertising.
The company had 954 groups in the system it killed nearly three years ago. Now GM is struggling in Detroit, Chicago, the East Coast and other areas. About 160 of the signed groups are in the top 50 markets.
"They've been down this road and they're just waiting to see how it really comes together," said Steve Tihanyi, director of marketing alliances and regional operations for GM. "There's a couple of West Coast markets that we did some testing in. There's some really good results there. As the dealers start hearing more about that, they'll see there really is value in doing this."
By the end of the year, the company wants 200 marketing groups in the major markets, said GM spokesman Terry Sullivan.
"We're also trying to get 50 percent of the sales-volume dealerships by the end of the year," he said. "We're about 40 percent of our volume right now."