Help Needed Truck wont start acting like battery is dead.

[Crusin350]

Ive been having nothing but bad luck with my truck this winter. It acts like the battery is dead when I try to start. It is the truck in my signature.

If i put a meter on the batteries while in the truck I usually read between 12.5 volts and 13.5 volts. When the truck has trouble starting i can leave the meter hooked up and when I turn the ignition on the voltage drops to anywhere between 6 volts and 9 volts and I hear all kinds of clicking under the dash. Sounds like all the relays under there are turning on and off randomly. I have taken the batteries out and had them load tested seperatly and both tested good. Ive done some of the tests that ive seen in other posts about voltage drops across wires and found that the battery cables appear to be good, no voltage drop at all between batteries. I also checked to see if there was voltage drop to the GPR and show no drop. I disconnected the battery feed to the GPR to see if it was some how causing my problem but this was not the case, I still show the same 6-9 volts when the key is in the on position. I have removed the module for my remote start/keyless entry to help eliminate that, but that made no difference.

The only thing that I have done that appears to make a difference is remove fuse number 20 under the hood. I took them out one at a time and this is the only one that seems to make a difference. The fuse is labeled "Ignition Switch (B4 & B5)" in my owners manual. With this fuse removed the votage with the key off is 13.5 volts and when the key in the first position (where you would wait to start) the voltage drops to 11.5 volts. Does anyone know what this fuse feeds, or has anyone had any similar problems?
Any input is greatly appreciated!!!

 

[Crusin350]

Update...
now the truck is doing the same thing with fuse #20 pulled. Voltage is dropping from 12.55 down to 9 volts with the key in the forward position or with the key turned backwards (like when you just wanna listen to the radio. I removed the radio and there is no voltage drop with the key in the back position but there is still voltage drop with the key in the forward position.

 

[Crusin350]

I do have the Edge program in the truck it is currently on level one, and has been for over 2 years now with no known issues. I am going to try to return the program to stock tomorrow after work. I did try to disconnect the alternator to see if this was somehow causing an inssue, but this did not make any difference.
I have also been having the battery light come on in the guages for over a year now, but has been on and off and was just counting on it being a weak battery.

 

[BIG JOE]

When it DOES start... what does the volt meter read ? should be 14+ volts... running. (Alternator gone bad, shorting to ground)

when you crank it over.. does it crank like normal.. or Slower ? (Starter going/gone south)

Joe

 

[Crusin350]

I had this problem a couple weeks ago and removed the remote start thinking that was the issue. I left the voltmeter hooked to my 12V acc plug and read a constant 14.5 volts everywhere I went for like a week straight. (I had no issues for 2-3 weeks)
I did take the truck to Advance Autoparts and had them do a test on the electrical system and the test didnt throw up any red flags. The results were kinda confusing, but I wasnt having any issues at that time so I didnt worry about it.
The batteries both tested good when I took them in and had them tested, but 1 hour later with them in the truck they tested ok. The test while they were hooked to the truck said that they need to be charged and were putting out 12.58 volts. When they did the starter test it said that the battery voltage was too low to test the starter. Ill try to scan the test results and post it on here tomorrow.

But to answer your questions...
They voltage is good while the truck is running 14+ volts
The truck appears to crank normal the only times I had trouble starting was when it was below the 40 degree mark and I didnt have the truck plugged in. But never seems to be slow crank, just lack of combustion probably due to weak or bad glow plugs.

 

[DaveBen]

My guess would be bad batteries. I know that you said you tested them, but did you witness the test? If your batteries are going down to 9 volts with just the key on, you have bad batteries. Replace them in pairs!!!!

Dave

 

[DaveBen]

Cancel my post above.

Dave

 

[Crusin350]

Bad batteries was my first thought. I purchased them from the dealer in january of 2006. They are 875 cca and both tested above 830 cca about 3 weeks ago. I may try to put a load on them from a source other than my truck to see if the voltage drops like it has been. I have a 1000 watt power inverter that ill hook to them tomorrow after work and see what happens. This may help diagnose a battery that is going bad.

 

[iracemine]

volt testing batterys mean nothing. you need to get them load tested individually. if one is low or dead, replace them both. volt meters are junk.

give your self a treat and go up to 1000cca too, you'll thank me.

 

[DaveBen]

After 4 years they are DEAD.

Dave