Idiot light was on for battery charging issues

Sanded all ground connections

Soldered battery cable connections

Scan gauge showed sporadic inadequate charging

Installed new alternator

Scan gauge showed sporadic inadequate charging

Installed new interstate batteries

Brought old alternator to be rebuilt, rebuilder said it was strong as could be, needed no work, high output alternator

Reinstalled old high output alternator

Scan gauge now shows charge output of 13.9 V to 14.1 V

Idiot light still on, flickers like a loose connection, sometimes lights constantly.

Occasionally speedometer fluctuates wildly, when fluctuating like this at idle, the truck will stall, so far it restarts...so far

When it has stalled the speedometer still fluctuates wildly for a few seconds truck will restart and seem fines but this will play out again next day or so

Occasionally ABS light comes on, occasionally water in fuel light comes on and they go away after abit, some times after a restart, not always though

Thought it might be cam positon sensor however not certain with the instrument lights also acting as they do

Have had one cam position sensor open circuit code once,

about to trip out west to Monatana & Colorado and back home to Ma in a couple of weeks, hoping not to be stranded somewhere in between those places!

Any Ideas?

 

Did you check all the grounds including body to frame, frame to battery, block to battery. How do the connections at the starter look.

 

I will check those again. Overlooked the starter...

 

You may have a bad PCM relay

Or wire

It's losing power and resetting the PCM when you see gauge sweeps

 

Starter ground was not the problem, I will check the pcm relay and wires.
I am wondering if more than one thing is going on. Might the instrument cluster need a rebuild, I understand they go bad. Battery light flickers, stays on, it goes off but rarely, scan gauge says 14.1 volts usually pretty constant, occasionally the abs and water in fuel light on, then they go off on their own. What throws a wrench in it is when the speed fluctuates/surges up it only stalls if I am not moving, like at a light but restarts and off we go. I did have the cam position sensor open code 1 time as well. any how thanks for your response.

 

Update: went over the PCM connections checking for corrosion, disconnected, reconnected, multiple times..no change
went over the alternator connections for the 20th time, ground coming out of alternator and the couple of small 2 wire connection...light is now out.
Water in fuel was on, shut truck off, on restart water in fuel light out.
Seems as though I did see the speedometer flucutating slightly.
Will see how it does tomorrow as I tool around for work.

 

I just sent my cluster to circuit board medics and got it rebuilt. It was doing all kinds of crazy stuff, and if I started the truck and the cluster was dead, it would cause the engine to miss, idle higher, and have reduced power. And the transmission would either tie up, or go into a higher gear, it would barely move. When the cluster finally lit back up, the truck would run fine within a minute or two.
If you could find a cluster with the same part number, it might be worth your time to swap it in. It only takes about 10-15 minutes. I put a donor one in my truck while the medics were doing their magic, and it worked fine.

 

John,
Well my battery light is still out. However today the speedo is jumping all around, loss of power, hard time getting out of its own way.
My cluster lights up, though, Guess I will be sending it out. Going to also try the PCM Relay as per Blad3es suggestion

 

You have to test the PCM relay with DVM

Or just replace it might be easier for you

Done much electronic trouble shoot before

 

I've never followed cluster issues but my gut feeling is if it runs bad as we'll the cluster would be later in trouble shoot
Because I don't know if a bad cluster would affect drivability
Unless a cluster is back feeding power to PCM or something weird

 

I would recommend at least calling Circuit Board Medics. They can help you decide if it COULD be IC related
https://circuitboardmedics.com/2002-...luster-repair/
Also, any problems with the windshield wipers? The was a owner that had problems slightly like yours that was caused from a shorted WS wiper motor.

 

Benny, I would love to know what was casing the feedback. Some other guy on this site had it happen too, he was the one that clued me in to it only causing trouble when the cluster would short out at startup. If the truck was running when it shorted out, the only thing that happened was the radio and windows wouldn't work, if it shorted out on startup, I didn't drive it until it relit. It always put the brake light on when it was acting up.

 

To update this thread. I called for dealer to see if they had a PCM relay in stock, The parts department and 6.0 mechanic was not aware of one for this truck.
So I popped the hood again to check for perhaps some abraided wire. Sunday,when I was last under the hood I saw the plastic nipple that has a hose attached to it which runs to the degasser bottle was cracked and leaking, I tapped in a metal nipple, coated the threads high temp silicone, reconnected the hose, no leak. In order to do that, I had to move the turbo hose out of the way. Neglected to hook that turbo hose back up... which is why the truck had no power monday... Monday after reconnecting the turbo, I removed the speed sensor from the rear end wiped it cleaned, and so far speedometer has been steady, not acting up yet. I intended to replace the oil in the rear end as well, bought the truck with 80,000 miles on it, now at 124,000, probably has not ever been done thanks for your help

 

Well , speedometer back to fluctuating wildly again, replaced speed sensor in rear end, check wiring at rear end for chafing, still jumps around.
Called circuit board medics, explained what was going on, they said not the instrument cluster, as more symptoms are usually found with it going bad. loss of power to the cluster, power in and out, other components not working etc. Am picking up a Cam Position Sensor today. See it that helps...

 

I doubt a cam sensor will change anything