OBD II code fix?

[blksmk]

Hey all of you psd experts I need your help. My '99 7.3's check engine light came on again. I plugged in the scanner and It threw P1391 - Glow plug circut low input (Bank #1) and P1393 - Glow plug circut low input (Bank #2). What does this mean in laimens terms. Also what exactly do I need to change to fix this. Thanks for your help.

Thanks again'
Adam

[NCHornet]

Check the UVC harness coming off each valve cover, pull apart the connection and look for any burn't terminals. I would also take a multi meter and check the GPR.

NCH

[blksmk]

Hey first off i'd like to say thanks for the info. What is the GPR suppose to be at, and what is GPR

[NCHornet]

GPR= Glow Plug Relay It is located just to the left of the fuel bowl and looks like a starter relay. There will be two of them, the one in the front is the fuel heater the one to the rear is the GPR it will be a round brown colored relay with two larger posts and two smaller ones. With Key on you should have 10.5 -12 volts on both large posts. If not your GP's are getting power.

NCH

[blksmk]

Thanks I appreciate your time