88 7.3 f250 diesel starter going out?

[Dodobrain38]

I tried to start my truck the other day and at first I heard the GP relay click once then I counted to 10 just in case they weren’t warmed up yet. I tried to crank it up, but all I heard was a quick clicking sound. Ok maybe the batteries or terminals aren’t good, tested both batteries sitting at 12.8V respectively and checked the voltage to the starter relay with the accessories on to see if it’s getting enough power from the batteries and it was. Now it’s getting a single click when trying to turn over the engine and the pulley will turn a little then shut off. Is the cable coming from the starter relay to the starter bad? Or is it a failing relay or bad starter all in all?

Also there appears to be a 3 pronged plug cable that looks like someone ripped off a vacuum cleaner that’s attached to the starter and it runs up to the top of my hood, any ideas what this is or could be used for? My theory was it was plugged into an outlet to get enough power for the starter to turn over the engine lol. TIA for everything

 

[IDIBRONCO]

Also there appears to be a 3 pronged plug cable that looks like someone ripped off a vacuum cleaner that’s attached to the starter and it runs up to the top of my hood, any ideas what this is or could be used for?

I doubt that's actually attached to the starter. It probably goes right over the top of the starter and attaches to the engine heater.

 

[Dane Rickford]

It sounds like a bad starter to me. And I believe that three prong plug is your block heater. The block heater plugs into the block right behind the starter making it appear it goes to the starter

 

[Dodobrain38]

I doubt that's actually attached to the starter. It probably goes right over the top of the starter and attaches to the engine heater.

So if it is attached to the engine heater what would be the use to plugging it in? Sorry I’m brand new to diesels.

 

[Dane Rickford]

I doubt that's actually attached to the starter. It probably goes right over the top of the starter and attaches to the engine heater.

Beat me to it @IDIBRONCO!

 

[Dane Rickford]

The block heater heats up the coolant in the engine when it’s plugged in, which warms the entire engine, and in turn makes for muck easier starts in the morning or in winter

 

[IDIBRONCO]

So if it is attached to the engine heater what would be the use to plugging it in? Sorry I’m brand new to diesels.

It's used when it's cold outside to help the engine start. It warms up the coolant. In Huntsville, you probably won't need it very often. It also can get your engine started if you use it if all of your glow plugs burn out. We all have to start somewhere so don't worry about being new to diesels. You've come to the right place to learn.