Do timers work in services?

[HongKongCV]

Do timers not work in services? I have a service that is running fine, has been for a while. I'm trying to add some work that needs to kick off regularly, so I create a timer that fires every 5-seconds and kick it off when needed.

The Tick event never fires. Never, not once.

I'm not sure why it doesn't work. Here's the relevant code I'm using. I have 4 backgroundworker threads named, simply enough, bgw1 - bgw4. I wil show you the code for one of the threads so you can see what I'm doing.

namespace PolicyMigrationService
{
    public partial class Service1 : ServiceBase
    {
        private Timer TimerThrd1;

        protected override void OnStart(string[] args)
        {
            base.OnStart(args);

            // Create the timers
            TimerThrd1 = new Timer();
            TimerThrd1.Interval = 5000;
            TimerThrd1.Tick += new EventHandler(TimerThrd1_Tick);

            backgroundWorker1.RunWorkerAsync();
            backgroundWorker2.RunWorkerAsync();
            backgroundWorker3.RunWorkerAsync();
            backgroundWorker4.RunWorkerAsync();
        }

        private void bgw1_DoWork(object sender, DoWorkEventArgs e)
        {
            Process200Policies();
        }

        private void bgw1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (NextPolicyIndex < PolicyCount)
            {
                int load = CpuLoad.Query();
                if (load > 90)
                {
                    // Processor full, kick off timer to detect when it is empty.
                    TimerThrd1.Start();
                    return;
                }

                // Processor not full, kick off thread to process more
                backgroundWorker1.RunWorkerAsync();
            }
        }

        void TimerThrd1_Tick(object sender, EventArgs e)
        {
            LogMsg("Timer Tick...", 1);
            int load = CpuLoad.Query();
            if (load <= 90)
            {
                // Processor not full, start the thread to process the next chunk
                bgw1.RunWorkerAsync();
                TimerThrd1.Stop();
            }
            else
            {
                // Processor full, do nothing
            }
        }
    }
}

So when the thread ends, I check the processor to see if it can handle more work. If not, then I kick of a timer that is supposed to fire every 5-seconds and do the same thing.

Only the tick event never fires. Does anybody have any idea why?