Our truck in the sig had been sitting for a very long time, and when I tried to start it a few weeks ago, the batteries were dead. Checked the fluid level and they were dry! Added DI water, jumped it and it started. We had also replaced the thermostat at this time so DH drove it about 8 miles to see if the temp was coming up (it hadn't been before the replacement). It sat for aobut four days before trying to use it again, and it was dead again. Figured it hadn't had a chance to charge up. Jumped it again, and drove about 120 miles without turning off. Started up fine after that.

Last Thursday we decided to take the truck on a Memorial Day vacation, driving about 300 miles to our destination. No problem. Used the truck for a couple of short trips. Then, time to come home. About 60 miles into the drive, the "check gauges" light comes on and the battery gauge is way low. We pull over and check connections. Our connectors are in rotten shape and need to be replaced; the ground cables don't connect tightly any more, like they melted at one point. Anyway, truck started up and seemed to be running fine so we decided to ignore it.

DH noticed the gauge dropping further so we found an AutoZone open on Memorial Day. Tested batteries and they were "BAD." Bought two new batteries - ouch $$$! The guy there brought out the tool to check the charging. Another guy in the store said it wouldn't work properly with two batteries. Gizmo showed only 12 volts but should have been 14 with engine on, correct?

We bought a danged alternator (ouch $$!) and were going to try to install right there, but it was more than we wanted to take on with the belt and all, so we decided to try to get home. We made it another 230 miles, 10 short of home, when the check gauges light came on again and the gauge had been dropping.

So, my Haynes guide talks about other testing that needs to be done to determine where the problem really is. Are there any other problem areas that could obviously account for this scenario? I don't want to dive in and replace the alternator if that isn't the real problem!

thanks in advance...

 

bad battery connections can do amazing things just to make you spend money. Best thing to do, is start the truck, run it until the grid heaters shut off, then test the output. You want to see 13.9 volts or greater at the output terminal of the alternator. then check the voltage at the battery connectors. If it matches, then check the voltage at the POSTS. Not on the connectors, but at the actual center of the battery posts. If this voltage is different, then you have a resistance between your cable ends, and the battery posts, causing a no charge condition.

If you have a meter with an amp clamp ( inductive ammeter ) use it to see how many amps the alternator is putting out. This will give a better indicator. High amperage can mean that there are accessories drawing too much current, or it can be indicative of a high resistance in the charging circuit. Perform the amp draw test with all accessories turned off. This will give you the nearest to true reading of what the charge circuit is doing.

Do all of these tests to determine what needs to be replaced. Because you have already said that the battery connections are bad, you might want to start there.

Good luck

 

I had a similar situation. Truck drove fine for about 2 hours on the way to purchase a new trailer. Hooked up, and headed home, when the warning lights came on and battery gauge was flipping out. I went through the batteries and alternator and found a loose connection on one of the cables. Cleaned/tightened everything and it was fixed.

 

With these trucks the connectors and cables are big honkin' things - do I need to buy the whole arrangement, or can the old connectors be cut out and new ones spliced in? I know, stupid question, but the whole assembly seemed pretty expensive last time I checked!

 

I cut them off and bought some hummer military bat. connectors and new crimp connector(I fortunately had the crimp tool) and most imp. I put dual wall adhesive shrink tube over all connection. we did my boys and my truck came out perfect. the premade ones are very expensive ED

 

Many truck or electrical (alt/starter) shops can make custom cables ar reasonable cost. Do not use the cheap bolt/clamp terminals. There are really good ones avaliable at mentioned shops or good truck parts store.

 

This is an old thread but my input on changing cables is, if they are loose and there is no more room for tightening take the bolt completely out each side the bolt screws into and simply put a hack saw to it. Now u can tighten as much as needed. U spent 0$'s