air intake heater sticking on ??

[List]

Recently my 05 ctd seems to be showing the volt meter in the slightly less than 14V position (normal is just above 14V for this trk) after start up. It used to cycle on/off a couple of times before turning off. Now I can hear the normal "click" which signals shut off but volt meter still shows lower volts. After a couple of minutes or so the heater does shut off and volt meter returns to normal. This is no big deal now but it is different than normal and I wonder if a sensor or switch is going or gone bad. I don"t even know the sensor is located. Any advice or info from someone with knowledge is appreciated.





List

05 CTD 2WD 6SPD

STOCK

 

[Prairie Dog]

Don't know where you are but if it gets cold enough the heater will stay on a lot more even even after it completely warms up.

 

[Wingate]

Easiest way would be to check for voltage present at the heater. If its there, I would think the grid heater is being controlled by the IATS and maybe coolant temp...

Cycle the key 3 times and see if there are any codes, maybe IATS going bad??? Also, have both batteries load tested and have the charging system checked...

remember, Garbage in = garbage out. .

 

[List]

I"m in southern Ohio but what my trk is doing now is not normal. It still cranks good on the original batteries. Until proven wrong I believe a sensor or switch has gone bad

 

[mwilson]

What happens if you strike off down the road with the heaters still cycling???



I think that they are supposed to cut out at 15 mph. Mine does for sure.

See if that function is still working correctly.



Mike.

 

[cerberusiam]

Being the volt gauge is a fake and bears no resemblance to what is actually going on in the electrical system, its tough to tell where the problem could be IF there even is one. Your batteries could just be worn and it takes longer for the ECU to see trhat they are taking a charge correctly, or, the cluster controller is not setting the gauge correctly until the rpms come up.



There are just too many things to even start with unless it is showing codes. If you have original batteries change them before chasing any more ghosts.

 

[JFought]

i have had the grid cycle when driving around 50mph when it was about 15* plus wind chill

(truck was warm, interstate driving)

 

[cerberusiam]

i have had the grid cycle when driving around 50mph when it was about 15* plus wind chill



(truck was warm, interstate driving)

Then your ECU is TU. Then again its an 06 and thats the typical condition for them. :-laf



As was previously posted, over about 15 mph the ECU locks out grid heater cycles if it is functioning correctly.

 

[Prairie Dog]

Cerb, I agree the meter is a bit of a show since it's programmed to "stick" when we first start the eng stop but after that it will reflect at least a trend of whats going on. I had a situation where something would cause my voltage to oscillate and the gauge ended up being very accurate.
Now the oil pressure ~ that as we both know is complete BS.

 

[JFought]

lol i hate this damn tipm system!!!

 

[JJPage]

You have two grid heater relays mounted next to your passenger side battery. One or both could be starting to fail because of worn contacts, if they fail stuck/welded shut, I have been told they will drain your batteries.

IIRC there was a member who was able to purchase a heavier generic relay from an auto parts store for quite a bit less than from Chrysler, and it was a direct replacement with no fitment issues.

Here's a link from an earlier generation truck: https://www.turbodieselregister.com...orum-1989-1993/181240-grid-heater-relays.html

 

[AH64ID]

My 05 doesn't bounce with the voltage, always reads low while the grid heaters are in operation. The actual voltage does jump up when it clicks off, but the gauge doesn't reflect it. Sounds normal to me.

 

[Prairie Dog]

My 05 doesn't bounce with the voltage, always reads low while the grid heaters are in operation. The actual voltage does jump up when it clicks off, but the gauge doesn't reflect it. Sounds normal to me.

That's how mine works too. Dodge freezes the meter so people won't call the dealership asking why their meter is jumping. Of course they still call wondering why the lights are dimming.

 

[AH64ID]

And then in 06 it bounces again.

 

[JJPage]

Sounds to me like the OP has been paying fairly close attention to it's operation in the past, and he states "it is different than normal".

Does the ambient air sensor in the air intake tube determine whether or not the ECU commands the grid heater to cycle on and off, it seems logical but I am not sure. If the OP is certain his truck is behaving differently than normal, then that is an easy sensor to swap.

 

[JJPage]

Easiest way would be to check for voltage present at the heater. If its there, I would think the grid heater is being controlled by the IATS and maybe coolant temp...

Cycle the key 3 times and see if there are any codes, maybe IATS going bad??? Also, have both batteries load tested and have the charging system checked...

remember, Garbage in = garbage out. .

And yes to this info.

 

[cerberusiam]

Just because it changes does not mean there is osmething wrong. It is still a fake gauge that is driven by a) what the ECU interprets b) the data put on the bus c) what the cluster controller sees d) what the cluster actually reads from the cluster controller.



The truck is almost 7 years old. Now idea on the condition of the batteries which will change the way the gauge reads. No idea if it has been to the dealer and if it was flashed which may very well change how it all works.



I have just listed about 50 different individual and combinations of events that will cause an intermittent different operation. Where does one start? Frankly, from his description it sounds like mine has always operated. The gauge has never returned to +14 immediately after the heater cylces off, it aways takes a 2-3 count and sometimes it never makes it to full charge before the next cycle kicks in.



I have noticed that lately the charge gauge is getting slower returning to normal position on a cold start along with intermittent slower than normal cranking when cold. My guess is the batteries are about borderline for holding a charge and on a cold start they get drained a little more than usual which takes more time to recover. Or maybe there is a bad connection or battery cable? Or? Or?



Too many failure points to pin point an issue or even say the operation is not "normal".

 

[Mikey-KE7LBB]

This is a copy & paste from a post that I just sent:



Oil Change Required - Dodge Cummins Diesel Forum



This may be caused by ECM not seeing the perfect voltage or feedback from one or more sensors.



Kinda unrelated to the specific issue, but It could just be bad batteries confusing or interrupting the signal to the ECM...



Keep it cheap by going to Autozone or O'reiley and have them load test each battery separately BEFORE digging in or replacing parts that may need not be replaced!!



Cold weather has given me MANY issues that have been solved by charging every few days or plugging in the block heater.

 

[rbattelle]

Does the ambient air sensor in the air intake tube determine whether or not the ECU commands the grid heater to cycle on and off, it seems logical but I am not sure.

That's correct, the intake air temperature sensor is used to determine grid cycling. There are separate pre and post heat patterns. Preheat is based only on the intake temperature sensor, whereas postheat also considers the engine RPM.

Preheat Schedule:
-40°F < T < 0°F --> both heaters run for 30 seconds continuously
0°F < T < 15°F --> both heaters run for 15 seconds continuously
15°F < T < 66°F --> both heaters run for 10 seconds continuously
T > 66°F --> No preheat

The postheat schedule is a lot more complex.
-40°F < T < 0°F --> both heaters run for 20 seconds continuously, then 1 heater for 10 seconds, then alternating between heaters on a 25/75 duty cycle for 120 seconds.

0°F < T < 15°F, RPM < threshold --> both heaters run for 10 seconds continuously, then alternating between heaters on a 25/75 duty cycle for 130 seconds.

0°F < T < 15°F, RPM > threshold --> both heaters run for 10 seconds continuously, then 1 heater continuously for 90 seconds (the ECM will alternate between the two heaters, but the net heat duty cycle is 100%), then alternating between heaters on a 50/50 duty cycle for 40 seconds.

15°F < T < 30°F, RPM < threshold --> both heaters run for 10 seconds continuously, then alternating between heaters on a 25/75 duty cycle for 130 seconds.

15°F < T < 30°F, RPM > threshold --> both heaters run for 10 seconds continuously, then 1 heater continuously for 90 seconds (the ECM will alternate between the two heaters, but the net heat duty cycle is 100%), then alternating between heaters on a 50/50 duty cycle for 40 seconds.

15°F < T < 30°F, RPM < threshold --> both heaters run for 10 seconds continuously, then alternating between heaters on a 25/75 duty cycle for 130 seconds.

15°F < T < 30°F, RPM > threshold --> both heaters run for 10 seconds continuously, then 1 heater continuously for 90 seconds (the ECM will alternate between the two heaters, but the net heat duty cycle is 100%), then alternating between heaters on a 50/50 duty cycle for 40 seconds.

T > 66°F --> No postheat

It gets a lot easier to see how the schedule works if you actively monitor the grids when it's cold.

For the postheat schedule the manual indicates that "intake temperature OR battery temp sensor" (emphasis added) is used to determine which pattern to use. Unfortunately, the manual doesn't explain how battery temperature comes into play. It may be that the ECM will alter the cycle if the battery temperature sensors indicate bad batteries, which might explain any deviations from the schedule the OP is experiencing.

-Ryan

 

[AH64ID]

Don't forget there are 2 sensors, intake air temp (IAT) sensor and manifold absolute pressure (MAP) sensor. They both provide temp/pressure data to the ECM. The temp derived from the MAP is what is used for pre-heat grid heater operation. The IAT sensor could show -30° but if the MAP shows 70° (i. e. from block heater operation) you will NOT get a WTS or grid heater operation before starting. After Post-heating will based on IAT sensor, and the MAP sensor temp goes up with grid heater operation.

So the MAP is for pre, IAT is for post, and the 05 manual states the battery temp sensor is only for charge voltage and has nothing to do with grid heater ops. I think the battery temp sensor is a carryover from 2nd gens and wasn't changed on early CR service manuals (much like min LP pressure).