03 Headlights and heater motor surging?

[Sea01Cummer]

Like the title says, i have a friend that has a cummins that his headlights and heater motor surge. This happens all the time and not just at start up. What could this be? Is the alternator pcm controlled, regulator wise? Any ideas would be great.



Steve

 

[Posm]

The grid heater will continue to cyle up until the motor starts to warm up and the speed exceeds 30MPH, Ithink. He needs to watch his amp gauge and see if it is going down and then returns to normal for the first 5 or 10 minutes. He may want to unhook the ground on the grid heater and see if this "fixes" the problem.

 

[p-Bar]

Shot in the dark: check the heater grid solenoids just below the rt side battery if you hear them clicking that could be the problem. Only thing on the truck that could draw significant current that you would notice other than the starter but you would realize that. Let us know what happens

 

[Sea01Cummer]

Thanks guys i'll do some checking and let you know.



Steve

 

[osiris]

hey i took my new truck to the dealership for this problem and they said it was "normal" until the engine warmed up a bit

 

[Viani]

the other night i noticed my dome light fluctuating and wondered what caused it, today i got literature from tdr as per my new membership. in the literature is has a packet of faq's. one of the questions dealt with this. it says cummins uses a grid type air intake heater. there are two cycles, pre-heat and post-heat. after the engine has been started the post heat cycle takes over. it the temp is 59 or below the heaters cycle on and off depending on air temp and how quickly the engine warms up. the heaters draw alot of amps, causing lights to fluctuate. once the engine is warmed up enough this should stop. it also says this is normal on all trucks manufactured from 94 to current, hope it helps.