Engine/Transmission (1998.5 - 2002) Grid heater diagonostic

[B-rad]

Well, here goes my first post.



Just figures the weather is getting warmer so harder to diogonse this problem. My 2001 w/the cummins started taking longer to fire when starting it. The lift pump was replaced about 8 months ago and I can hear it cycle when I turn the ignition.

If I plug it in it cranks over faster in the cool mornings. It also starts great on a hot day, just not on a cool morning.

Are the grid heater relays the same for #1 and #2? Can I buy one and just mix/match until it works?



Also, I turned on the headlights to see if the power is drawn down when I start it in the morning and it is not fluctuating, making me think the grid heater is engaging. this is even on cool mornings.



Thanks for any input.

 

[Mr. C]

Welcome B-rad



You should be able to see the toasters cycle by just watching the amp meter in the instrument cluster, mine swing the needle enough to notice.



Can't tell you for sure but the relays look the same to me.



A factory service manual is a good investment and it will give you the diognostic flow charts to pin down your problems.

 

[Graphic man]

Glad to have you aboard B-Rad



The ECM controls the heaters, check all the grounds first and you should see a good drop in Voltage in the lights and the meter on the dash with the keep on.



keep us posted to what you find



Scott

 

[B-rad]

Yeah, I am not getting any kind of drop in the voltage when starting after letting my garage cool down. last time it was probably 55 worst case more like 45. I can't believe both relays could go bad at once. Kind of feels like I am snipe hunting but diesle style. Huhhuh



Could someone tell me where all the grounds are? Thanks for the responces. Truck still starts when it is warm... . new fuel filter, batteries, lift pump.



My truck was hit in the front passenger corner once. ???

 

[ryecreek]

Off hand there is a ground Batt (pass side) to block and 1 at intake horn if i remember correct

as said get a service manual 100 very well spent looks like 5 of them books at napa that cover 10 years but only covers yours (1500 2500 3500) the are very decriptive too. step you through everything nothing like the napa deal there very much like a equipment manual if you have seen one

Geno's has them in stock

 

[B.G. Smith]

Yeah, I am not getting any kind of drop in the voltage when starting after letting my garage cool down. last time it was probably 55 worst case more like 45. I can't believe both relays could go bad at once. Kind of feels like I am snipe hunting but diesle style. Huhhuh



Could someone tell me where all the grounds are? Thanks for the responces. Truck still starts when it is warm... . new fuel filter, batteries, lift pump.



My truck was hit in the front passenger corner once. ???

-----The grounds for the heaters are at the rear side of the air horn where it enters the engine, the two wires on the front side are coming from the heater relays. If you have a test meter you could check continuity through the heaters with the engine off to see if the grid is still good or check for voltage on the front wires when the engine is first started at temp. below 59 deg. f to see if voltage is there to determine if the heaters grid or the relays is the peoblem. bg

 

[B-rad]

Well, the problem has seen to go away. Went camping and both mornings it started fine, probably 45F out. maybe the problem is gone. ? Both mornings I watched the voltage meter and there was no drop or fluctuation. ???



Thanks for any input.