View Full Version : Troubleshooting 4 flashing lights - open high temperature limit switch
pearson2
Dec 18, 2008, 07:05 PM
Thanks for your input. I finally was able to reverse the wiring and got it squared away. While I was in the attic I thought I would replace the motor which drives the fly wheel. I thought I was a hero till I put everything together and discover 4 flashing lights. The lights indicate "open high temperature limit switch." Can you help?
acetc
Dec 18, 2008, 07:22 PM
The limit switch will probably have to be reset by pushing in on the button in the middle of the limit switch. The switch may be on the blower houseing or the front of the furnace, look for red wires to a small round device. Good luck ,Mike
pearson2
Dec 18, 2008, 07:26 PM
Thank you Mike... I am on my way to the attic.
pearson2
Dec 18, 2008, 07:45 PM
I checked and couldn't find anything related to your description. I check the blower and tried to identify the limit switch and couldn't and I did find 2 small circular "things" with small red buttons but neither pushed in. I tried following the red wire and it lead to a harness which is connected to the ignition control board.
KC13
Dec 18, 2008, 07:58 PM
You had reverse polarity before, right? Maybe correcting that has advanced you to this code... check module wiring vs. diagram. Pay attention to limit circuit connections.
pearson2
Dec 21, 2008, 07:36 PM
Hello, it is an extremely cold night. However, I was able to get my system for function to it's potential. The limit switch(s) were tough to find but after diggin in I found two switches and these switches are on the top and bottom of the blower. You will see two wires; a yellow and red one. You have to look really close because the reset button is between the leads where you connect the yellow and red wires. You should use a screw driver because it was tough to push down. Thanks to everyone who helped.
Blooma
Nov 16, 2009, 05:47 PM
THANK YOU VERY MUCH! These tips allowed me to repair my "high limit switch" with ease. You're right... it's a very small reset button connected to a red and yellow wire.
KC13
Nov 16, 2009, 05:52 PM
You treated the symptom... what was the cause? Check your air filter; replace if clogged.