generator light coming on.

[RPhCummins]

I left the pharmacy tonight and was about 2 miles into my 5 mile commute to home when the "GEN" light came on. I looked at the battery meter and it was laid over to the left like the heating grid was on. About a minute later the gauge returned to normal, however the "GEN" light was on. Got to the house and turned off the truck and turned it back on again. Guess what! No generator light.

Any idea what's going on? This hasn't happened before. I'm going to try it in the morning to see if I can get a repeat performance.

Anyone have a diagnosis?

Thanks
Chet

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1996 Long Box Club-cab, K&N filter, misplaced silencer ring, kitty and muffler are history, totally stock otherwise, 255/85 R16's, just waitin' to get bombed, Rocky Mountain Elk Foundation Member, Pioneer stereo system.

 

[Tom Schuster]

I had the same problem with my '97. The fix for my truck was a new alternator. Unlike the 89-93 trucks the voltage regulator is not a separate part. The no charge condition (GEN light on) would go away after one or two shut downs and restarts.

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[Tom Trujillo]

Check out my recent post in the 2nd Gen non drive train forum. The same issue just cost me over a grand. Read and head. Tom

 

[Hootguy]

Hi RPH
I have that problem too,,,check your grid heater relays for sticking,,,,mine did it and would kill the batteries,,,when the relays are energized the PCM doesn`t let the alternator charge constently,,,,even if the grids relays unstick the Gen light usually stays on until you cycle the key on and off agin. . Check it out soon before iyt cost you a bundle,,relays are cheap,,,also check the temp sender,,it too like to go bad ,,,,
I cut the trigger wires and linked them to a switch in the cab so i can dissable the grid heaters just in case it want to do it again and leave me stranded somewhere,,,
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,Bill Kondolay DTT torque converter and valve body,K&N filter,Mag-Hy-tek transmission and diff covers,Isspro triple pillar gauges,60 gallon transfer tank,Rld topper,

 

[Jff24Gordn]

Mine does that too. It happens every once in a while, and I just wiggle the wires on the alternator, and it goes out.

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1996 2500, 4x4, 5 speed, pscotty air, 15. 813 second 1/4 mile @89. 35 mph STOCK parts
-- email address removed -- Great Lakes TDR
PURDUE STUDENT 
GO BOILERS

 

[Missouri Mule]

Could be heaters sticking. Also could be bad wiring or conections , battery temp sensor(located under drivers side battery) ASD relay which supplies line voltage reading to EVR contained with in the PCM.
Try to get code off PCM it will rule out some and save you on quess work.

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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

 

[rhoads]

2 cents
IF the ALT!! stays on and the tach also is not working and as i rememberthe ?? blower?? not sure on that one BUT remove the fuse cover panel cover left side of the dash panel and you will find a blowen plastic fuse. as i rember it is a 5 or 15 amp 2nd or 3rd row down to the left end.

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96-3500 SLT EXT. CAB AM/FM/CD-RINO LINER. D-CELERATOR EXH. BRK-RED LINE VAC. OVER HYD BRK CONTROL- AIR BAGS W/HVY DUTY AIR COMP. PUTCO S/STEEL DEEPBOARDS FRONT TO REAR. REESE 20K 5TH WHEEL & GOOSE -REESE 20K HITCH BELOW W/17K RECEVER. CLEAR COATED & SOUND DEADINGING &UNDER COATED 5 SPD/W 4:10 MCHLN'S 235/16'S UNIDEN PC76/WEATHER-WILSON 1000 MAG MOUNT ANT. 4 WHL ANTI LOC BRK SYS.
750,000 miles