Bad Alternator?

[RWherley]

My check engine light came on in my 93 D350 when i checked the codes i found DTC 41, a short or open circut has been detected in the generator field control circut. dose this mean my alternator is going bad or is it my voltage regulator. I have noticed the volt meter in the dash dose move up and down from time to time but has only left the operating zone once when it fell to the bottom of the gague.

 

[HHhuntitall]

Check the alternator, if it's still good, it's probably the voltage regulator.

 

[DVolk]

It could be a bad connection since the positive batt cabel has all the wires on it

 

[HHhuntitall]

Oops, I see you have a '93. The voltage is regulated by the PCM, so there is no external voltage regulator... ... Yeah, battery cables can effect it. Also, the wires that go to the back of the alternator can get worn into, and the main charge line can get corroded where it connects inline close to the battery.

 

[RSchwarzli]

I have never diagnosed anything on these trucks by way of computer... .

How does one check this? Is that the flashing center brake light count and dont screw up method?

 

[dodgenstein]

Cycle the key on-off-on-off-on leaving key in on position after 3rd on cycle. The "check engine" light will flash the Diagnostic Trouble Codes. Then use a service manual to interpret the findings.

 

[DVolk]

If you have a scanner that reads the 90s cars it will read it the odb 1 , it was called

 

[RSchwarzli]

Oh. OBD trucks. Yeah. Ok. The 90 does not have this hence the wonder.

Right. Following now.

 

[RWherley]

It turns out it was the altinator and after a rebuild kit from Geno's it works good as new, and yes I used an OBD reader to find the code.

 

[RSchwarzli]

Good to hear!