Archived Complete electrical failure

[TboneMan]

2001.5. I used me truck this morning and it ran fine.

I went to start the truck this afternoon and noticed now that I have complete electrical failure. Nothing illuminates (dash, headlights, dome lights). Turn the key and nothing. Absolutely nothing (yes, that is completely...nothing).

I pulled the 140amp main fuse and it is fine. Batteries are fine.

Am I missing something?

 

[mwilson]

Check the fuse with an ohm meter, could look ok but still be wasted. Or take a test light and start working your from the battery, both sides of the fuse and then poke around in the power distribution box. Something simple or a lot of green corrosion somewhere.

Mike.

 

[TboneMan]

Check the fuse with an ohm meter, could look ok but still be wasted. Or take a test light and start working your from the battery, both sides of the fuse and then poke around in the power distribution box. Something simple or a lot of green corrosion somewhere.

Mike.

I tested the fuse with a meter. It is fine.

 

[mwilson]

Is there any power on the incoming side of the fuse holder? I am trying to remember how the year truck is wired. Doesn't that feed come directly from the LH battery positive cable terminal?

 

[mwilson]

Could be a fusible link there somewhere as well.

 

[seafish]

Bad or corroded connection of ground wires from batteries to frame??

 

[DonFitzwater]

Bad or corroded connection of ground wires from batteries to frame??

X2 on the ground path

 

[TboneMan]

Well, now that there is some sun light and the temps are above 0f, I took another look at his. Both batteries, which are only 3 months old) are toast. Both read 6v. Something must have fried them. Any clues?

 

[JR]

Are you positive you didn't leave anything on?

Once you get the truck running check the charging voltage from the altenator.
It's possible you got 2 bunk batteries, but not likely. Or possible one was junk from the get go and the alt overcharged the good one because the pcm only sees voltage from one battery.

I brought home a brand new Interstate for the wifes Beetle TDI, and it was junk from the get go. Showed just over 7 volts on the multi meter. I didn't realize it until I got the dang thing wrestled in, I was not a happy camper. When I took it back for another one I took the multimeter and verified voltage before it even left the counter.

 

[Sticks]

Are you positive you didn't leave anything on?

Once you get the truck running check the charging voltage from the altenator.
It's possible you got 2 bunk batteries, but not likely. Or possible one was junk from the get go and the alt overcharged the good one because the pcm only sees voltage from one battery.

No, the PCM sees total system voltage. Both batteries are connected to each other, so the PCM can not distinguish between either one.

Common problem of late, grid heater relays getting stuck in the on position. What color is your intake horn on top of the grid heaters? Carmel colored?

Lots of potential suspects here. Going to have to start with fresh batteries and start doing systematic checks to find the issue.

Charging of the alternator

Amperage draw with the truck turned off (you will need an amp meter)

Positive and ground connections

 

[TboneMan]

No, the PCM sees total system voltage. Both batteries are connected to each other, so the PCM can not distinguish between either one.

Common problem of late, grid heater relays getting stuck in the on position. What color is your intake horn on top of the grid heaters? Carmel colored?

Lots of potential suspects here. Going to have to start with fresh batteries and start doing systematic checks to find the issue.

Charging of the alternator

Amperage draw with the truck turned off (you will need an amp meter)

Positive and ground connections

We have a winner!!!! The 1 year old alternator also fried. And the intake cone does have a carmel colored coating. I've been suspect of the grid heater for about a month. It just seemed to be acting funny. Like this morning. 12 deg F, start the truck (using "Wait to Start). I back out of the driveway and the grid heater is already cycling off (no excess draw on volt meter) and lots of white/blue exhaust. At that ambient temp, the grid heater shouldn't have turned off until 15mph.

Something's fishy with that system.

 

[JR]

I re read my above post and see where the misunderstanding is. When the charging system is honkey dory then yes both batts will charge equally. But if say the driver side is shorted or there is a poor connection between the 2 batteries then the pass battery will overcharge.

 

[Sticks]

We have a winner!!!! The 1 year old alternator also fried. And the intake cone does have a carmel colored coating. I've been suspect of the grid heater for about a month. It just seemed to be acting funny. Like this morning. 12 deg F, start the truck (using "Wait to Start). I back out of the driveway and the grid heater is already cycling off (no excess draw on volt meter) and lots of white/blue exhaust. At that ambient temp, the grid heater shouldn't have turned off until 15mph.

Something's fishy with that system.

You could have one or more problems here.

Start with fresh batteries. If the Alt is still not charging, have it tested. It is controlled by the ECM, and those have been known to go Tango Uniform (READ - the function that controls the alternator). There is a fix that does not involve replacing the ECM if the alternator comes tests as being OK. IIRC there is a way that you can do the test on the truck, taking the ECM out of the loop, but how to do it, I don't remember.

Once you get that sorted out, then it's time to test the Grid Heater relays (x2). Do a search in the 2nd gen Engine and Transmission section. There are 3 or 4 threads in the last 3 months or so about them, and various methods of testing them.

 

[Missouri Mule]

The grid heater(s) should cycle on and off (taking turns) until reach 15 mph or 5 minutes. But if you were blowing smoke they mite be acting up (usually white).

 

[Sticks]

Acting up, or burnt out and broken.

Each of the two pull 95amps when running. A simple test is to disconnect the hot legs and ohm it out. Should be less than 1 ohm resistance across each leg of the grid heaters (hot leg to engine ground, and again to battery ground.

 

[CM_Guest]

I was wondering how they were reading only one battery for the PCM, lol. That cable setup is kind of a joke. When you've got two batteries in parallel but send the current through one cable to the starter, that's not a true parallel system. I think there's a guy online that builds custom battery cables for our trucks. They're not cheap but NO good battery cable is cheap and the ones that ARE cheap are the most expensive of all. Done properly, there should be a cable from each battery directly to the positive terminal on the starter solenoid with a pigtail cable coming off that point to a common connection point with the alternator and a good cable from the alternator to that point. Then take accessory power from that point.