None of the gauges work and won't crank

[Vj318]

I have a 98.5 24v cummins 4x4. I know very little about electronics so I'll need lots of help. A few weeks back I had to make a trip of about 30 miles in the dark. Bout 10 miles in I think the alt quit working. When I got to my destination the voltage was down to 8v. In about 3 hrs a friend put jumper cables on it for about 10 min. Tried to start it but got nothing not even a click. Check several fuses but all appear ok. Got under truck jumped starter with screwdriver and it started up but no gauges worked and not charging batts. All else worked so drove truck home the 30 miles. Recharged batts and tried again but got nothing. Did gauge check where gauges do 1/3 1/2 then full sweep then back to resting. Continued test and got several codes like I think 910,921, 940 and so on. Don't remember all of the codes that came up,but I can redo test. No bus did not come up. Please help

 

[JR]

First things first you need to check the state of your batteries with a voltmeter with the truck off. A load test is preferable but knowing the voltage after the truck has been sitting for a while is a good indicator also. They need to be properly charged before diagnosis of any other issues as this could be the cause of everything.

 

[Vj318]

Batts new

 

[JR]

So, what is the resting voltage of the batteries? And when running? Proper voltage is necessary before any other diagnosing.

 

[Vj318]

Resting voltage.12.45v. Less when running cause alt not charging. Won't crank with key. I have to jump it at the starter

 

[PBJ2500CTD]

I assume from what you have stated about all the gauges are not operating includes fuel, water, oil and voltmeter. If so, is the check gauges light and chime triggering? Headlights must be working if you were traveling in the dark. Are there any other electrical issues like lights, interior, external, HVAC, cruise, etc.
It sounds like two systems are affected and keeping with the "KISS" principal where one issue is causing all I would check for common things that have recently been accomplished. How long ago were the batteries changed; were they both changed out at the same time with identical, quality batteries? Check all of the battery connections. Remove, clean and tighten the terminals and all ground points. Do the battery cables look a little swollen, especially near the terminals? Could be internal corrosion problem. The "900" series codes given may indicate bad wiring or a faulty PCM. Check the PCM connections. Ignition switch and loose connection in the PDC can also contribute to the simultaneous failures. Fuses, relays and switches are independent in the charging and starting circuits. Still, it would be easy to swap the relays around for troubleshooting purposes.

Independent circuits:

Starter:
Battery connections
Park/Neutral switch
Solenoid
Fuses
Relays
Bad battery

Charging:
Bad Alternator
Bad PCM
Fuses
Relays
Bad wiring


Best of luck.

 

[JR]

12.4 volts is roughly 50% charged....not good. Need to get them on a trickle charger to bring them back before irreversible damage is done to your new batteries.

Have you gone through and checked all your fuses and relays? It almost seems as though you have two separate issues going on. If the main alternator fuse is good I'd pull it and get it bench tested and replace if necessary. Beyond that and testing of individual fuses and relays pcm determines charging rate, also control many of the functions you have lost .

 

[DavidC]

Some wiring diagrams may help to start troubleshooting. Here is the Starter

Dave

 

[Vj318]

One batt new other older but good. cables in good shape. All fuses good. interchanged a couple of relays still no crank. All lights inside and out work everything else works.just alt not charging, no gauges work and won't crank with key. Thanks for the schematics I'll take a look at them.

 

[PBJ2500CTD]

Check points:
PDC Fuse Gen (140A) Just for Alternator issue
PDC Fuse 10 (50A)
Junction Block Fuse 9 (10A)
Ignition Switch.

These points "may" affect the instruments, PCM/Alternator and starter. It sure would be nice if there was a schematic for the PCM to see how the circuits process the data. There were a couple other circuits/fuses involved, but less likely due to associated functions apparently operating, like indicator lights.

 

[Vj318]

All fuses good

 

[PBJ2500CTD]

Pointing more to ignition switch or PCM.

 

[Vj318]

Will try to get back to the truck later this week

 

[dblake]

I have a 98.5 24v cummins 4x4. I know very little about electronics so I'll need lots of help. A few weeks back I had to make a trip of about 30 miles in the dark. Bout 10 miles in I think the alt quit working. When I got to my destination the voltage was down to 8v. In about 3 hrs a friend put jumper cables on it for about 10 min. Tried to start it but got nothing not even a click. Check several fuses but all appear ok. Got under truck jumped starter with screwdriver and it started up but no gauges worked and not charging batts. All else worked so drove truck home the 30 miles. Recharged batts and tried again but got nothing. Did gauge check where gauges do 1/3 1/2 then full sweep then back to resting. Continued test and got several codes like I think 910,921, 940 and so on. Don't remember all of the codes that came up,but I can redo test. No bus did not come up. Please help

I had

 

[dblake]

I had a similar issue years ago. Turned out to be the ignition switch going bad. Simple and cheap.