the battery?

is it controlled by the ECM on a 93 D250?

 

The state of charge of the battery goes to the regulator [ thats in the ECM ] the reg then gives a variable ground to the field wire [ more ground more charging ] .

 

so if the ECM malfunctions, then the battery is not charged, correct??

 

I been in the repair bis for while , and the way to fix a problem is with a test to confirm whats wrong .
You are jumping a lot of steps , not the whole story in the 1st post , there are many other items to look at , or can cause the batteries to not charge , including the batteries .
I mainly mention this to save you money & grief , not to offend .
I missed the hacked part from your sig , sounds like you have a long term project on your hands .
I think the 1st thing to do , is get a factory [ only ] shop manual , to start putting things back to stock , some will tell you to put an external regulator on the inner fender .
The ECM is about the last thing to cause the batteries not to charge , load testing the batteries , atl & starter , clean connections , look at fuses , there is a ASDR [ auto shutdown relay ] in the wiring for alt .
Just takes a lot of patients to get rid of all the problems .

 

If you already have a hack job, you may just want to check out the thread in the sticky about retrofitting an old style external regulator to your charging system and eliminating the regulator in the ECM.

https://www.dieseltruckresource.com/...n&onlynewfaq=1

Depends on whether you want to wire it back to stock or just make it work. Your choice.

 

thanks guys.

the current issue with the ctd is :

factory guage cluster failure

OD failure

cruise control failure

possible ECM failure

the 1st 3 mentioned problems are the only electronically controlled items on this model (as far as I know) that are controlled via ECM.

I have also heard that with some 1st gen CTD models, the ECM controls the alt's capability for output to the battery.

my preclusions run the route of ECM failure across the board thusly affecting the output of the alternator.

I did apply my digital auto ranging multimeter to the battery with the ctd at idle. I found 11VDC at the battery, and 0 at the alt cable that directly connects to the battery.

in essence, it shows no power from the alt, but if the alt output is electronically controlled, then the ecm is the culprit.


my alt was installed about 4 months ago..

I have disconnected the alternator wire harness and sprayed the connectors with CRC electronics cleaner removing numerous years of build up.

removed the main wire harness plug from the fire wall and ecm to clean once more with the CRC spray cleaner.

yes, I disconnected the battery first.


ok , heres another question. when I connect the negative bat cable, I get a small arc. is that normal with all accessories and ignition off?

 

There is always some draw on the batteries , clock & radio memory at min .
A multi meter is very limited in testing for loads , a load meter is a special tool that you not normally find outside of a repair shop , besides having to have about 15 + volts , you need to measure up to 1,000 amps .
A very limited [ with out load tester ] test for the alt is to disconnect the wire going to ECM , from the ECM & touch to a good ground for a few seconds while some one is watching the gauge to see if the volts come up to at least 14v idea , batteries discharged & 1,800 RPM about 16v .

 

John


I am a bit lost in your descritpion of disconnecting and testing the alt.

I believe that therte is a similar write up in the DIY area. I will look.

thanks.

 

The wire that controls the alt , goes to the computer , what almost all devices that are controlled by ECM do it through ground side .
So testing to see if every thing but the ECM works , disconnect the wire going to the ECM [ you do not want to jump the alt with out disconnecting the ECM , because you could kill the ECM ] then touch that wire from alt to ground [ only for a few seconds , because that full fields the alt , and thats not good for more that a short time .
That will check everything , connections on the alt side , but does not prove the ECM is bad , 2 small wires at back of alt , one goes to power + , thats through the auto shut down relay , fuse , then ECM , the other small wire goes to the regulator in the ECM - this the wrong term PCM = Powertrain Control Module , just to clarify .
I was looking for wiring diagram , but my source did no have one for 93 , the 94 should be close but I have figured out how to put here .

 

I found a write up here...

https://www.dieseltruckresource.com/...18&postcount=4


it is about as clear as mud.


heres my question about pcm check.

do I leave the harness connected to the unit and pull back the rubber boot on the connector to check the pcm voltage?

still looking for a wire schematic of the pcm connector and related harness connections ot the alt.

 

This is as close as I have at this time , its for a 94 , it should be good enough for testing .
But disconnect at alt [ the wire going to the PCM , and then jump to ground the stud on alt for just a few seconds , this will check the alt , wiring & most connections .
If the alt puts out [ remember you need a load tester=Amps , to do a complete test ] , then the other parts like fuse , auto shut down relay , fuse .
Let me know if the link works .

http://arrc.epnet.com/autoasp/framerq.asp

 

What exactly isn't working in the gauge cluster?

No OD and cruise, Have you checked the crank sensor and wiring, if the PCM isn't getting a signal from the crank sensor it will act like the engine is not running, won't charge the battery, etc......

 

the WHOLE factory instrument cluster is non functional after a couple miles of driving.



when the engine is started, all instruments on the dash function properly. after a mile to 10 miles of driving, the whole cluster shuts down. no: speedo, temp, alt, oil, etc.

this truck has digital feed to the analog guages. yep, a big wire harness plugs into the instrument panel backside and feeds the analog guages.

my low fuel indicator in the middle panel worked just fine last saturday

what I am trying to figure, is whether the PCM is the main controller for the non functioning equipment.

could it be the crank sensor as was mentioned?

I have a very good price for a PCM right from Dodge if it comes down to it.

I am going nuts with this ctd.

I do NOT desire to sell it.

 

If your keeping , get a factory shop manual .

http://www.genosgarage.com/prodinfo....r=DFSM93_PRINT

 

I plan to get a fsm soon.

I was going to buy a group 31 battery for my truck. maybe I should order the fsm instead