Engine/Transmission (1998.5 - 2002) Short in wiring,battery?

[cgoder]

I seem to have a constant battery draw that will leave the truck unstartable after about a week. The batters are 2 years old and I have had them tested and they say there good by doing load test. I have heard about a cell shorting out that acts like this. If not where to start? Do you have any great ideas?

 

[SnoKing]

You can connect two wires to a number 97 bulb. Disconnect both negative battery terminals and connect the bulb between the terminal on one battery and ground. If it shines brightly, start pulling fuses and relays until it goes out to find the circuit that is drawing the power. SNOKING

 

[cgoder]

Thanks for the idea. I will give a try this coming weekend

 

[Bob4x4]

You can connect two wires to a number 97 bulb. Disconnect both negative battery terminals and connect the bulb between the terminal on one battery and ground. If it shines brightly, start pulling fuses and relays until it goes out to find the circuit that is drawing the power. SNOKING

A test lightwould be easier

 

[cgoder]

Are you saying to go between the pos and neg of the same battery to light the light and then start pulling relays?

 

[PBJ2500CTD]

Are you saying to go between the pos and neg of the same battery to light the light and then start pulling relays?

No... Disconnect both negative battery terminals. Then connect a test light from the negative terminal of either battery to ground. This will complete the circuit and if there is current flow the light will illuminate. Kind of a poor man's ammeter.

 

[JZellers]

It still could be your batteries. I had the same thing happen to me on my Excursion with batteries that were less than a year old when I started having the problem. They load tested fine and would start every day but leaving it for a few days or any abnormal draw like working on it with the hood and door open for an hour would not leave enough voltage to start it.



The guys at the local Interstate store where I bought the batteries told me that something in my truck had to be draining the batteries so after I spent a great deal of time and money troubleshooting, I bought two new batteries (NOT from Interstate) and the problem went away. Basically the reserve capacity died and it didn't take much to drain down to where it wouldn't start.



It's probably not a cell problem because if a cell fails in a normal 8-cell battery, you'd see 1. 5 volts less on a volt meter (10. 5 for one cell collapsed).

 

[cgoder]

So if the light does not come on there is no short and bad batteries?

 

[PBJ2500CTD]

As a poor man's ammeter the bulb's filament will illuminate if there is a sufficient current draw. Depending on the bulb's characteristics the circuit may have too small of a draw to cause the filament to illuminate, so it is not a precise measurement of the circuit's activity. However, it will give an indication if there is ample current. Then you would start pulling each fuse until the light goes out. That will indicate which circuit the problem is in.

When the shop performed the load test, were the results on each battery the same? If one battery is weaker than the other it can draw the good one down.

 

[cgoder]

I do not know if the load results were same. They just said they were good. I will mhave to have it done again with that question

 

[Silver_Ram]

Was the load test with batteries in or out of the truck? Were the negative cables disconnected on both batteries? I have seen a lot of places that load test with both batteries hooked up. Alot of times one battery will be dead & the other battery will be trying to keep up with it all.

 

[cgoder]

All right Guys

I have had a test light hooked up for days now during testing. I have not seen much between all the fuses under the hood or inside the driver cab. I can only get the light to go out if I pull the 50 amp fuse that says battery under the hood. Than if I hit the break,turn the light switch on,hit the dome light,any thing that would draw power and the light comes on bright. Any great ideas please?

 

[lschleif]

I just went through this myself. A test light won't gt the job done unless you have a heck of a draw. There are numerous posts about battery draw, but here is what I did:
1. disconnect both positive cables from the batteries.
2. On one battery connect a test light in series (from the positive cable to the positive battery terminal.
3. With the driver's door switch securely in (turning off the light) wait 30 minutes for all the timers and everything to go off. Note, if you loose connection to the batteries your 30 starts all over again.
4. See if the test light lights if it doesn't after 30 minutes you need a DVOM.
5. . take a digital volt ohm meter and read the load while leaving the test light hooked up.
the meter will read the load as the juice goes through it easier than the light.
6. Your goal is less than 30 milliamps. Mine was at 150, wouldn't light a test light but would drain batteries in 5 days.
7. Pull fuses one at a time and see where the draw is. When you see which fuse you will need to find out everything on that circuit.
8. Mine was a relay I had installed for some back up light.
This is going to take some time. Also don't forget about the 30 minutes and the timers as it will give you a false reading.
Hope this helps.
Larry