Dead in the water

[wilcfr]

I own a 1997, 5.7, 4x4, automatic, 2DR Tahoe that I bought about 7 years ago. It's mostly just a retirement project though I do drive it around town and in the winter time. I've put way more into it than I'd ever get back if sold, but that was never the point. I always wanted one and I have had a blast working on it. However, I've run into a problem that I need some advice on. The truck sits outside and isn't driven much so I keep a battery tender on it to keep things charged. I went out a couple of weeks ago to drive it and it wouldn't start. I assumed the battery, which was three years old, had given up the ghost during the extreme cold snap we had around Christmas, so I invested in a new one. I installed the new one and still nothing. I checked the battery and it was fully charged. I checked all the big fuses under the hood and they are all good. The cables to the ECU looked solid. I've got no headlights, dome light, horn, power seats, fans, radio, nothing. I'm guessing/hoping it may be a bad ground cable because that would be easy enough to replace. The battery cables on the top end both seem to be good and secure. I even replaced the positive bolt because the old one was was a little rusty and rough around the edges. Really don't want to have it towed if it's something I can fix myself. I'm reasonably handy with a wrench and have testing equipment and lots of tools, most of which I've acquired since purchasing the truck. If it's something reasonable that a 70 y/o can get to to fix I'm good. Any suggestions as to what to look or test for would be appreciated

Thanks for you help.

 

[NardDog]

rats! I would start with the ignition circuit. My first thought was chewed up wires.

 

[B-train]

Doss your truck have the mega fuse on the firewall that comes from battery positive and then feeds the fuse box? It's been awhile since I worked on one of those, but all the newer models have that.

You could also take voltage readings and work away from the battery to any junction and see where you lose power. Also check continuity to ground from the battery and other ground connections.

 

[wilcfr]

rats! I would start with the ignition circuit. My first thought was chewed up wires.

We have a goodly number of tree rats around here that chew up everything they can get their little teeth on. I'll check that? Thanks.

 

[Doubeleive]

I own a 1997, 5.7, 4x4, automatic, 2DR Tahoe that I bought about 7 years ago. It's mostly just a retirement project though I do drive it around town and in the winter time. I've put way more into it than I'd ever get back if sold, but that was never the point. I always wanted one and I have had a blast working on it. However, I've run into a problem that I need some advice on. The truck sits outside and isn't driven much so I keep a battery tender on it to keep things charged. I went out a couple of weeks ago to drive it and it wouldn't start. I assumed the battery, which was three years old, had given up the ghost during the extreme cold snap we had around Christmas, so I invested in a new one. I installed the new one and still nothing. I checked the battery and it was fully charged. I checked all the big fuses under the hood and they are all good. The cables to the ECU looked solid. I've got no headlights, dome light, horn, power seats, fans, radio, nothing. I'm guessing/hoping it may be a bad ground cable because that would be easy enough to replace. The battery cables on the top end both seem to be good and secure. I even replaced the positive bolt because the old one was was a little rusty and rough around the edges. Really don't want to have it towed if it's something I can fix myself. I'm reasonably handy with a wrench and have testing equipment and lots of tools, most of which I've acquired since purchasing the truck. If it's something reasonable that a 70 y/o can get to to fix I'm good. Any suggestions as to what to look or test for would be appreciated

Thanks for you help.

I would test for power & ground starting at the battery to fuse box and battery to ground, just probe around a bit you might find the problem pretty easy that way, clean up the grounds, meaning unbolt it and hit it with a wire brush and re attach even if it looks "ok".

 

[wilcfr]

That was kind of next step. I'm hoping ground since that would be the easiest to deal with. Thanks.

 

[Hoesgottaeat2]

The positive terminal has a tendency of having a compromised connection over time, especially since it's one side post coupled/fastened over the top of another. This creates (2) connections that can fail on the positive instead of just one. Be sure to pull both sections apart and clean with a wire brush.
Check for positive power at the power distribution box under the hood, at the starter and the alternator. This will verify a good connection amongst all supplied by the positive post.
Overcoming this one myself as we speak on my '96.
The long cranks I was having intermittently for over a year(caused by a bad D-cap) led to that positive terminal taking a beating and getting burned up.
My battery has both side and top posts available, so I've converted the positive side cable to a top post. Availability of a terminal that will accept all (3) wires is what led to this decision. Inexpensive and simple solution.

 

[wilcfr]

The positive terminal has a tendency of having a compromised connection over time, especially since it's one side post coupled fastened over the top of another. This creates (2) connections that can fail on the positive instead of just one. Be sure to pull both sections apart and clean with a wire brush.
Check for positive power at the power distribution box under the hood, at the starter and the alternator. This will verify a good connection amongst all supplied by the positive post.
Overcoming this one myself as we speak on my '96.
The long cranks I was having intermittently for over a year(caused by a bad D-cap) led to that positive terminal taking a beating and getting burned up.
My battery has both side and top posts available, so I've converted the positive side cable to a top post. Availability of a terminal that will accept all (3) wires is what led to this decision. Inexpensive and simple solution.

Thanks hadn't thought of that. I may need a new positive connector.

 

[B-train]

As @Hoesgottaeat2 stated, the side post terminals like to get green around the edges and in between the 2 pieces sandwiched together. Back in my younger days, that was a common repair when replacing a battery.

The cables of that era seemed to hold up well, I don't recall replacing any (but that doesn't mean that the same year vehicle 20 years later won't have that problem). If you separate them and clean them up well you should be able to see if the cable itself is corroded. If it seems good, then slather those 2 pieces with dielectric grease and reassemble.

If you need to repair the cable or put on a new end, I highly recommend the solder loaded ends and some good shrink tube. Great connection and pretty weather tight. They sell them at grainger, McMaster Carr, etc.

 

[YukonGTmaster]

I have had green corrosion at the positive and negative leads when mated up to the battery. I would make sure they are clean and shiny copper colour.

I have had success disconnecting them from the battery and hitting them with water and baking soda and a brass bristle brush. Then if needed light sand paper, and hit them with a Deoxit type contact cleaner/enhancer. Could be just a bad connection.