Gen.Light comes on. D.C.can't help.

[Skydiver]

Twice now on 40 degree mornings have noticed my volt meter at < 12. Then within 15seconds the gen light will come on. I will pull off the road and restart. Sometimes it will happen again and sometime volt meter will show 14. 5 with no gen light. Could it be the grid heater relay sticking and where do the 2 large relays on left wheel well get their control signal from? It might not be the grid heater causing this gen light to come on but who knows? Can not get it to the D. C. shop with the gen light on since restarting seems to make problem go away. Still under warranty.
The local Dodge boys said "We dunno nuttin bout dim dezul wires"
Batteries are new. Please help me!Before I jump out of an airplane.

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96 3500 Feline deceased. Electric start
Ready to upgrade. 86K. auto,3. 54,Ext. cab.

[This message has been edited by Skydiver (edited 01-29-2001). ]

 

[Andy Morrison]

I'm pretty sure the grid heaters are controled by a temp sensor in intake and the PCM. Does onboard diagnostics give any codes? Hope this helps.

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'97 2500 4X4 club cab, BLACK, Leer XL-100,running boards , cup smoothie, EZ Drain, 103,000 miles

 

[Extreme1]

The sensor tells the ECM to turn on the heaters. Depending on how the circuit is wired (feedback to ECM) this could be your problem. Next time, try unplugging (carefully!!) the heater relay and see if it fixes it.

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'94 3500 4x4, 208,000 miles, Never had a cat, Auto w/shift kit (thanks Dave G), 3. 54 Gears, TST #5 plate, 235-85-16s, Rancho 9000s w/remote, Isspro gauges inplace of cupholder & Amsoil Air Filter & Lubes, AWOL intake boot (put the silencer ring after I pulled the boot-too loud!?!). NRA member. Blue Ribbon Coalition member.
"Warrantee? We don't need no stinking warrantee!"

 

[Missouri Mule]

Skydiver,
I don't think your heaters are causing your generator light to come on. When in post cycle my volts drop also but light doesn't come on.
I believe your problem could be charging system related. Check wires/connections,sensor(battery temp)/connection, asd relay, engine speed sensor connection.
My quess is you are loosing your charge voltage that is why your light is comming on.
Battery temp sensor is working off and on no charge, same with asd relay both of these components send the EVR(?) which is located in and is part PCM(computer)The EVR regulates charging rate of alternator(generators voltage out put).
ECM uh that's for the over valved ones forum.
ECM = engine control module. #ad

The correct number vavled ones engines are not controlled by a computer just monitored. #ad

Have a nice day #ad


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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000

[This message has been edited by Missouri Mule (edited 01-30-2001). ]

 

[Hootguy]

Hey Skydiver,,
I have the same truck as you,,and also the same problem as you,,,,when the grid relays stick on,,the computer tells the alternator not to charge and lights the GEN light,,i shute the truck off and i can hear the relay releasing,,restart and everything is fine again,,,all i did was isolate the relays so if they stick i can manualy shut them off before both batteries go dead in a real hurry,,those stupid relays seem to go bad a lot. Athough not a permanent solution,,i just start the truck with no grid heater help ,,easy when plugged in.
Good luck,

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blacked out,96 3500,black,ext cab,KMC Slam,chrome aluminum wheels,continuous wheel balancers,Diesel Dynamics fuel plate and AFC kit,16cm housing,Dunnrite torque converter,Trans-go diesel shift kit,K&N filter,60 gallon transfer tank,Rld topper,

 

[Skydiver]

I'm not sure, but it seems like if the alt was not charging the GEN light would stay on when cranked. The second time this happened I tried restarting 7 times for my entire 14 mile trip to work and GEN light kept coming on. After the truck sat parked 45 minutes the problem went away.
On the grid heaters I've located the 2 solinoids on the wheel well,where is the relay that sends these units their control signal?Or is the control signal coming from the computer?
Thanks for the input.

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96 3500 Feline deceased. Electric start
Ready to upgrade. 86K. auto,3. 54,Ext. cab.
K&N air

 

[Missouri Mule]

Skydiver,
You found the heater relays.
Air intake temp sensor(located in Intake manifold behind grid heaters(intake manifold heaters)wire connector attached to it.
Sensor sends info to PCM, PCM tells the relays(by grounding them) to send power to heaters.
I don't believe generator light will stay on when cranking(engine not running). One, most components are shut down except those that are invloved getting the engine running.
Two, the engine speed sensor has to be able to send info to PCM off hand I don't know at what rpm the sensor starts sending. I do know it does when tach is measuring rpm. The engine speed sensor also sends info to TPS and turns on ASD relay. The ASD relay sends line voltage to EVR in PCM along with the battery temp sensor info this how the EVR determines how much volts/amps the Alternator(Generator) puts out.
I think I misunderstood your first post. You think your intake heater is coming on while driving down road. I thought your intake heaters were coming on right after your engine fired up, which is known as the post cycle.
Yes possibility heaters are coming on. One of the wires could be grounding out or it mite be another wire shorting big time.
Generator light should come on if juice is being lost from batteries and no juice is being put back in.

[This message has been edited by Missouri Mule (edited 02-03-2001). ]