How to Replace Glow Plug Switch on Ford 7.3L Diesel
  • Please read this manual carefully before installation. 
  • Please also refer to your vehicle service manual with this manual. 
  • After the installation has been completed, please keep this manual for future reference. 
  • If the installation was done in a shop, please make sure to give this manual to the owner. 

Kit Contents 

  • Glow Plug Switch

Required tools 

  • Your vehicle workshop service manual
  • Mechanic’s tool kit


  • This product was designed specifically for the application specified. If an attempt is made to use this product on another car other than specified, you will risk damaging this part and or components related to it. 
  • Do not use any excessive force when installing this product as you risk damaging the product or other parts. 
  • This product must be installed with the appropriate tools and equipment to prevent any electrical failures, injuries, or bodily harm.  

WARNING:  Do not use a screwdriver or a similar tool to pry the terminal cover from the glow plug relay. Battery voltage is present at the terminal.

Preparing for replacement 

  1. Park your vehicle.  
  2. Engage the parking brake to keep the wheels locked. Ensure your vehicle will not move. Shut off the engine and ignition, and remove the key from the ignition switch. 
  3. Open the hood and disconnect the battery, removing the negative terminal first. 


  1. Locate the Glow Plug Switch. If needed, remove any parts necessary to get to the glow plug switch.
  2. Remove the glow plug terminal cover.
  3. Remove the nuts and wiring from the Glow Plug Switch.
  4. Remove the 2 nuts that keep the Glow Plug Switch fixed.
  5. Replace the old Glow Plug Switch with the new one.
  6. Install, fix, and connect the other removed parts and wiring in the reverse order. 

If you do not feel confident doing the job yourself, have a certified technician perform the replacement.