Battery temp circuit question

[Dumb A]

02 ram 3500-6 speed manual 4x4.

If the battery temp circuit is open will this prevent the PCM from charging/regulating? I checked ohms between C1 pin 4 and C3 pin 15 on the PCM and found this circuit to be open. 

[Mopar1973Man]

Do you have a P1492 or P1493 codes?

[Dumb A]

No codes.

[Dumb A]

I just ordered a one wire Bosh retrofit for this truck from HEIELECTRIC. Has anyone use these folks, they are located in Oregon. 

[Mopar1973Man]

Can't say that I have. It is strange it should throw a code if the circuit shorted or open. 

[Dumb A]

I don't have any history with this truck, unfortunately. Many of the fuses were missing in the PDC and I was able to figure out from the skematics which fuses I needed. Everything seems to work now except the charging. I double checked green and blue wires for shorts and opens, they checked out good. I have ground on green and no voltage on blue. When I replaced the PCM and checked voltage on blue, it was 8

volts. Batteries were 12.2 volts. An odd thing I noticed today was after running the truck for 10 minutes or so the bolt meter dropped to 0 and the warning "check gauges" came on. At that time I had the charger hooked up to the batteries and battery voltage was 12.4 volts. Very odd!!

I will double check the battery temp circuit tomorrow to make sure I had the correct pins as the numbers are wonderfully small.

[Mopar1973Man]

10 hours ago, Dumb A said:

I have ground on green and no voltage on blue. When I replaced the PCM and checked voltage on blue, it was 8

 

PCM is damaged. I've got a protection fuse mod to stop this issues. Still need to send the PCM in for repair. The blue wire should be +12V after crank signal is sensed. Then the green wire should be variable ground after crank signal sensed. 

 

My alternator shorted out and burned a hole right through the PCM's printed circuit board. @pepsi71oceanhad the same failure and his was repairable through @Auto Computer Specialist.

 

The PCM master fuse is a 20A fuse. The problem is the circuit board can barely handle 5 to 7 amps before burning up. Hence the article was wrote up to stop the PCM damage. I'm running a 5A fuse and still going strong.

 

 

Edited December 9, 2020 by Mopar1973Man

[Dumb A]

Hey buddy, thanks for your help!!!

 

So I had read about this mod, adding the fuses link to the blue wire and performed this mod prior to installing the refurbished PCM. I will change the 7.5 to a 5 amp fuse. 

 

I got this PCM from Auto Module Source, I feel it didn't work from the moment I plugged it in, but not having much experience with this truck and lack of knowledge is a good recipe for self inflicted oh #@&$ moments. 

 

Thanks again for all your help and support. I will order a new PCM from Auto Computer Specialists.

 

I wish for you and your family a healthy happy future...

 

Mario

[Dumb A]

Update, I just installed the one wire Bosh and the system is charging at 14.2 volts at idle and wot.

[IBMobile]

1 hour ago, Dumb A said:

Update, I just installed the one wire Bosh and the system is charging at 14.2 volts at idle and wot.

Great, and the AC voltage out put <.05 ? 

[Mopar1973Man]

Bosch are not as easy to rebuild. ND alternators are super simple to rebuild. 

[Dumb A]

I was able to take the truck out for a test drive, seemed to go ok. It did set a 0120 code and the throttle did have a hesitation when it set this code. I measured the ac volts as described and got .043, engine hot, at an idle. I cleared the code and will see if it returns. You folks are a great help, thanks.

 

Mario

As for alternators, I will have one of each, Bosh and ND one wire converted by Heielectric in Oregon. That way I have a spare for when I'm up Alaska way having fun....