Testbench giving unknown (x) on output

module led_glow(
    input clock,
	 output led
    );

reg [5:0]count;

always @ (posedge clock)
	begin
		count <= count+1;
	end
	
wire [3:0]PWM_in;

assign PWM_in = count[5]?count[4:1] : ~count[4:1];

reg [4:0]PWM;

always @ (posedge clock)
	begin
		PWM <= PWM[3:0] + PWM_in;
	end
	
wire out;

assign led = PWM[4];
//assign led = out;

endmodule

module led_glow_test;

	// Inputs
	reg clock;
	reg [5:0]count = 0;
	//reg [3:0]PWM_in;
	//reg [4:0]PWM;
	
	// Outputs
	wire led;
	localparam T = 100;
	// Instantiate the Unit Under Test (UUT)
	led_glow uut (
		.clock(clock), 
		.led(led)
	);
initial begin
	clock = 0;
	forever
		#T clock = ~clock;
end
	initial begin
		// Initialize Inputs
		//count = 6'b0;
		//PWM_in = 4'b0;
		//PWM = 5'b0;

		// Wait 100 ns for global reset to finish
		#100;
        
		// Add stimulus here

	end
      
endmodule