Intermittent Charge Indicator Light

[BigLakeDMAX]

Greetings! The charge indicator light on my '02 has been illuminating intermittently the past week. It goes on for 10 - 15 seconds, then off. This happens usually after I've been driving for more than 30 minutes/miles. The voltage gauge does not drop and still indicates it's typical 15 volts even when the charge indicator is lit. I added a second alternator over 2 months ago and have had no problems until now. The only way I can duplicate this is to pull the connector to the main alternator and leave the aux alternator running. Both alternators are charging - I've pulled connectors on both alternators, one at a time, and the other continues to charge. I'm now running with the aux alternator disconnected to see if it reoccurs and if so, if the voltage drops or remains solid.

Anyone else had this problem or have an idea where to look? I hesitate to take it in as they'll likely blame it on my aux alternator install and charge me for the visit.

Thanks,

Don

[ 05-03-2003: Message edited by: BigLakeDMAX ]</p>

[ndamico]

Hi,

I have the exact same problem you do. i've had it since day one. my truck came with factory dual 105 alts. dealer says no code/no problem.

last week when i got my predator i checked and there was a code set, P0622 i believe. cleared it, and the second my batt light comes on, the codes pops back up. i haven't taken it back yet but it points to some generator problem. i've never checked my alternators individually, but it does set a code.

do you have access to a scan tool? i'd like to see if you have a code set too. note-my SES light was NOT on but the code was present.

mine also takes a bit of driving before it comes on. i think it has something to do with the OBDII diag cycle..

[BigLakeDMAX]

Thanks for the reply - interesting to note I'm not the only one here with this issue. The truck is going in today for some other work - I'll have them check for stored codes. My SES light has also not come on for this. I'll post my findings after I get the truck back.

[ndamico]

thanks..i've been wondering about this problem since my truck was new!

[2DAMAX]

I too have had the exact same problem It is very intermittent posted this last year and no responses,Let me know what you find.

Thanks Steve :eek:

[BigLakeDMAX]

I also had code P0622 stored. The tech working on my truck felt it was not a huge issue and he was focused on other problems for me that day and I needed the truck back that night. So far, I haven't had it happen since I got it back.

The Helms manual describes this code as resulting when the duty cycle of the alternator exceeds set parameters of 5% - 100%. In other words, when the main alternator duty cycle drops below 5% for more than 6 seconds. A sensor in the internal regulator provides the duty cycle percentage to the ECM. The ECM adjusts idle speed to compensate for the load on the main alternator.

Based on this info and my observations and tests, I believe that operating the aux alternator in some way periodically causes the main alternator to stop charging for a few seconds at a time. My truck ran just fine with the aux alt disconnected and the voltage stayed constant. The charge indicator has only illuminated with the aux alt connected. It has set both at 65mph and at 20mph while driving with constant engine speeds. It has not set at idle.

The Helms manual states that intermittent problems such as this are commonly caused by poor connections or damaged wires. It interesting to note that one of the fixes for this problem includes replacing the PCM (powertrain control module).

My plan is to continue driving it and see if it continues or worsens. If so, back to the dealer it goes for day 20 in the shop.

Good Luck!

Don

[oyazi]

BigLake ~ are both of your altnrs 105As? I've delphi 105 & 125A and can't say I've an issue w/the setup ~ but then, I donno what you mean by charge lite ~

Maybe not related but understand that some folks were having trouble w/their prodigy setting false ground open codes because of their electrical power arrangement. There may be something happening on our power buss that we aren't aware of.

Noticed that factory doesn't really make the dual altnr option public knowlege after the first yr of production.

[BigLakeDMAX]

oyazi - I have the 105A Delphi main alternator and added a 130A Delphi as the auxilliary. The charge indicator light is the battery icon that illuminates for 3 seconds after the engine is started. It lights if charging voltage is below 12 volts or above 16 volts, or if the duty cycle percentage is out of parameters.

I have a Prodigy also and have not had the 0.g problem reported with those units. The electrical system overall is very sound on my truck. I'm thinking there's no actual problem here, rather just an annoyance.