Weird problem. Replaced electric rad. fan with dealer part. Installed and fan does not run with air on. Checked relay and pulled high speed relay. Fan then runs. I re-plug high speed relay and fan kicks into high speed for a split second and shuts off completely. I proof this doing it several times same results. Switch relays around in box with same results. I then unplug low speed relay, fan kicks on. Re-plug low speed, fan kicks on high for a split second and completely turns off. So, with both high and low relays plugged in, fan does not work. If I take out one or the other fan will run and it appears at low speed. The fan had to be replaced due to wear with worn out contacts 110k. Any suggestion please on this weird event.