DETROIT -- General Motors said on Wednesday it was raising the retail cash rebates on most of its 2003 and 2004 model year vehicles to $5,000, Reuters reports. The rebates on many of GM cars and trucks, including its popular SUVs, minivans and pickups, had previously been set at $4,500. GM said its $5,000 cash-back offer could be applied only to current owners of its vehicles. For new customers it said it would continue to offer hefty discounts as well, along with a variety of interest-free loan programs. Meanwhile Ford Motor Co. said that its incentives program would remain essentially unchanged this month. However, Ford is raising the cash rebate on its Freestar minivan by $1,000, setting it at a new high of $5,000 in a bid to increase sales, Ford spokesman Jim Cain told the news service.The offer applies to customers seeking to finance their vehicle purchase through Ford's finance arm, Ford Credit, but those getting their auto loans elsewhere are eligible for a cash rebate of $4,000, Cain said.