Walker motor stalls when trying to engage blades??

Hi I've got a 1995 Walker model C GHS with the 16hp Kohler motor in it, the mower has been great to me up till now its a lil older so the wiring on the machine is a lil chopped up but like I said I never really had a problem with it. I went to use it yesterday and it started up with no problem but when I went to engage the blades there was nothing, after a while of messing with the wiring I got the blades to engage but as soon as I hit the blade switch it squeals like always but the motor dies out. I thought maybe a bearing froze up but everything turns freely by hand but every time I engage the blades with the motor running it trys to engage but kills the motor. If theres someone out there that could give me something to try out I'd appreciate it, Thanks.