Engine/Transmission (1998.5 - 2002) Grid Heater Disconnect

[dsd88]

Hello,



Installed a manual switch to disconnect the grounds on the solenoids to prevent cycling as others have done with the oil pressure switch. Works fine except check engine light comes on. If I turn switch back on and go through 3 startups it goes off. Any way to prevent this.





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1999, 2500 4WD, All original.

 

[jwinnie]

dsd88,



I have to give another member credit for this Idea but I don't remember his name.



I disconnected the grounds on mine also but instead of using a manual switch I bought a standard single pole oil pressure switch (can't recall the part #) and mounted it on top of the oil filter housing. This way the grid heaters function normally before startup but when the oil pressure comes up it shuts them off.



Works great and it has never set any codes on the dash.



Hope this helps,



John

 

[Michael Hughes]

Can I ask why you don't want the grid heaters to cycle?

 

[Lama]

Jwinnie, did you use a "idiot light" type switch that is normally grounded when no oil pressure is sensed (idiot light on), and open when oil psi is detected (idiot light off) ?



If so, what part number switch did you use if you can still remember.













Thanks

 

[csevers]

Some ECM's will set codes when the intake circuit is interupted and some don't, with the PS heater safer and my stock ECM I had the codes set in the ecm but not turn on the light (no problem) but once I put the T M ecm on the check engine light stays on all the time and I have talked to a couple of people and can't come up with a way to get it to go out.



Craig

 

[truckstom]

https://www.turbodieselregister.com/forums/showthread.php?threadid=58553&highlight=grid+heater+fix



this will show you the way... I don't know about the codes tho... . your's is the first one I've heard of that did that, 'course we didn't put a switch in. Maybe that's what's wrong??

Good luck tho...

 

[jwinnie]

Lama,

It's in the thread above, Borg Warner part #S320

Thanks truckstom,



John

 

[dlange]

Mine set the codes, when I left them unhooked 2.

 

[dsd88]

Thanks to all for responses.



Michael: I usually park in a garage and it gets just cold enough (approx. 40 degrees) to cause the heaters to cycle and I see no reason for them to cycle. Wear & tear for no reason.



truckstom: I've read the messages you suggested and that is what prompted me to do what I did. Can't see the difference between me flipping a switch and oil pressure doing it ??



Maybe I will check into the PS heater saver.



Thanks again,

Scott





--------------------------------

1999, 2500 4WD, All original.

 

[15w40]

The ECM not seeing a rise in intake air temperature before starting the engine causes the Check Engine Light. This sets code: P1291, No Temperature Rise Seen From Intake Heaters. If you allow the intake heaters to operate normally for the “Wait to start” period, and then disable them you will not set the Check Engine Light, but set two other codes: P0380 and P0382, Intake Air Heater #1 and #2 Control circuit. These two codes get set when the ECM sees an open circuit to the heater relays.



I am running the Practical Solutions system saver, which disables the intake heaters after the coolant temperature comes up. I scanned for codes and found P0380 and 82. The oil pressure switch will cause the same two codes to be set but not the MIL. The grid heaters are designed to come on when the intake air temperature is below 66*F (19*C) and are not controlled by any other sensor except speed. Above 18 MPH the intake heaters will stop cycling.



Hope this helps.

 

[Ncostello]

15W40... what do you mean the oil pressure switch will set the P0382 and P0380 but not the MIL. Whats the MIL? Do you mean the check engine light caused by no heat rise before starting?



Does the check engine light come on if you instantly go to start the truck without allowing virtually any time for the grids to do their thing before cranking? Just curious as I always wait for the light but I'm sure some folks dont. Seems to me this scenario would also not allow for any heat rise in the intake before starting.

 

[15w40]

The way the oil pressure switch is used to disable the grid heaters will allow normal operation for the “Wait to start” period and will not set the MIL (Check Engine Light). After the engine starts and the pressure switch opens and disables the heater relays, the two codes will be set because the ECM cannot see the relays.



If you interrupt the “Wait to start” by starting the engine, the ECM is smart enough to not look for the rising intake air temperature. I guess some programmer for the ECM figured out that you are in a rush.

 

[dsd88]

15w40,



I have tried waiting till the heaters cycle a couple of times after the engine is running and then turn the switch off. All good for about 15 seconds then the ck engine light comes on. Must be something weird with my truck?



Thanks

Scott

 

[Texas Diesel]

I think the above mentioned thread covers this pretty well. The only codes I have ever set are grid heater relay A & B fault. Neither one will turn on the check engine light. My truck runs flawless, had it in the teens many several times, as stated elsewhere, the grid heaters (after startup) are strictly emissions related nonsense. The "open on rise" oil pressure switch is to supply ground to the relays proir to engine start, after it is running the "open on rise" contacts are not supplying ground to the relays and the heaters stay off (and the relay fault codes are set).



dsd88, your situation is unusual, normally the check engine does not come on.

 

[Ncostello]

I'm never in a rush. I like to hear my lift pump run through its little act and then hear the grid heaters make their little noise. Amazing what you listen for in a quiet garage. Then after all that my fuel pressure gauge is flashing 0psi and the mighty Cummins will start faster than I can let go of the key.



I suppose those codes are no big deal as long as you can clear them out if needed. Are those codes just for diagnosis by a dealer to find a problem with normal grid operation? ie: bad grid element?

 

[dsd88]

Thanks for replys.



dsd88

 

[15w40]

Dsd88,



There must be differences in ECMs. My shop manual shows that some codes are set for CARB only and others for CARB and EPA. I guess I am lucky since in 1998 it was only a CARB code and the Check Engine Light stays off. It must be a California thing.



There might be one thing to check. I was wondering why the Practical Solution fix used two thermo-switches to keep each relay to the grid heaters separated. It would be cheaper to just use one thermo-switch and tie the two relays together but for some reason two are used. You might try separating the two relays by using a double pole switch to ground the relays. When the switch is closed, both relays will be grounded to allow normal operation and when the switch is open, both relays will be disabled and separated. Now the two grid heater circuits cannot talk to each other through the common switch connection.



I think this may be a long shot, but it might work.

 

[dsd88]

15W40,



That is the way I wired the switch. Thanks for suggestion though.



Thanks again

dsd88

 

[WestTN]

grid heaters

Letting them do their thing as designed does put a little wear on the solenoids, but the engine starts faster when the air is preheated. As long as those solenoids are less than $400. 00 apiece, I'll put the wear on them and save that $800. 00 starter!



They reduce air pollution by reducing unburned hydrocarbon emissions in the post-heat cycle. They also contribute to faster engine warmup and thereby reduce engine wear.

 

[Dog Hauler]

I just installed the PS system saver and am getting the MIL and setting the codes P0380 and P0382.



Do any of you think this could be related to a California emission issue?



Dog