So I just replaced both positive and negative battery cables for both batteries on my 2000 7.3 Excursion with new OEM cables. Cleaned connections on starter relay while all cables were off and took all ground points down to bare metal before reattaching grounds. Put batteries back in and now I am not getting any power at all (i.e. no dome lights, gauge lights with key turned, etc). Truck was running before I took batteries and cables out. Batteries were out for about 2 days (waiting for cables to ship) and were on trickle charge while out.

What did I do wrong? The only thing that I think that may possibly be causing this is I did use dielectric grease on ground connections and starter relay connections to prevent future corrosion.....am I wrong for doing this? Electrical is my weakness but don’t mind learning if somebody is willing to teach me (oh and have plenty of patience! Lol).

Thanks for any and all assistance

Double check the batteries too. Doubtful they would have both died while out, but you never know. Eliminate the simple stuff first.

If they are good, maybe stick the old cables back on one at a time to see if the problem goes away.

So after thought about carlton_webb’s response and getting some much needed R&R, I broke out the ohm meter this morning and started measuring some voltage at multiple points.

Batteries: good. Now to the starter relay. I know for a fact that I put the fusible links on the same terminal on the relay that they came off. What I do t remember was the orientation of the lugs coming from the battery cable. I remember thinking to myself that the lugs on cable were different sizes but the terminal posts on the relay were the same size so I didn’t think much of the orientation and herein lies my problem. I checked voltage on both posts, found the hot one which was opposite of the fusible links, and made the swap. Engine is now turning over. Thank all of you for your replies and insight. I was just tired and cold last night and needed carlton’s response to prompt some late night pondering and much needed rest.....and I haven’t even had my coffee yet!!! Lol

So so now I have another question which originally led me to change out the cables and I think that I know the answer to this one. I notice sometimes on my CTS2 that I only get between 115.5-12 volts and then it will pop up to 14.1-14.3. This morning when I cranked her up, I noticed on the CTS2 that it was reading 11.5 volts and immediately suspected the alternator (I was already suspect of it but was hoping that my horrendous cables were the cause). I grabbed my meter and tried measuring hot to ground on the alt while she was spinning......measured 14.5 volts. Scratched my head and peeled into the cab again and CTS2 was reading the same now. So I am thinking that the alternator is going and in need of replacement. Thoughts?

I would update the thread title but not sure how to do so from my smartphone which is being operated by someone not so smart. Thanks again guys.

To add to my above post, historically once the alt starts reading 14.1 or above it stays there throughout the drive. The low voltage is typically only on startup and the first few minutes (figuratively speaking) of running.

And since my brain seems to be working this morning (may have something to do with the sunshine beaming down and warming my dome!), I do know remember when I sometimes would run the heater in the winter that the volts would sometimes drop down into the high 13s, and subsequently go back to 14+ when I shut down the blower, which correct me if I am wrong is indicative of a faulty and/or failing alternator.

Thanks Denny. And I appreciate everybody’s insight. I take each nook of knowledge try to get smarter. Thank you all.

Well that’s what I thought and didn’t knock on wood before claiming victory! Ugh I hate electrical. So sitting and running I was at a steady 14.1. As I always do after making any repair and/or maintenance I jumped in to take for a test drive. Shortly after turning out of my driveway, voltage dropped to 12.5 volts. Stayed fairly consistently between 12.4-12.5. The more it ran the lower it went with the lowest that I saw being 12.2.

As as soon as I pulled into the driveway, I popped the hood and grabbed my meter to confirm the readings that I was seeing. Red probe on alternator output bolt and black to ground......12.5 volts. I am thinking that alternator is no bueno. What say the masses?