I replaced the heater core in my 1998 F150 5.4l. It was my first time doing this, and everything seemed to go well. But now when I try to start my truck, it just clicks. I cleaned the battery terminals. I can jump it to get it started. Is this the starter, and if so, is there something that could have caused the starter to go bad while replacing the heater core?

Thanks for your help. I'm new to this forum, and the heater core instructions I found on here were awesome.

 

If you can jump it to get it started, it's most likely the battery. Jump it, let it run or put it on a charger over night and see if it holds a charge.

 

I jumped it, let it run, and charged it. But it still just clicks when I go to restart it. All the power seems fine. Jumped the terminals on the relay - still won't start. Does this seem like the starter?

 

I would think that if the starter was bad you wouldn't be able to start the truck even with a jump start. My money is still on bad battery. I believe auto zone will test your battery for free.

 

Success! I checked, cleaned and tightened all of the terminals and connections thoroughly - now it fires up just fine. I am going to have the battery tested just to be sure. Thanks for the help!

 

Yeah, almost any parts store will test your battery for free, and if it needs to be charged they'll do that as well. It's better to have a charger charge your dead battery instead of working the alternator that hard anyway. You can use some dielectric grease on those terminals too. It'll help prevent corrosion from giving you problems down the road.