Engine/Transmission (1998.5 - 2002) Oil pressure switch to shutoff Grid Heater Relay

[CToney]

Is there any problem wiring in an oil pressure operated switch to disable the grid heaters after startup on an '01? I am going to do this on my '97 and was wondering if anyone has tried it on a '01? I am curious if the pcm would have a problem with it.



CR Toney

 

[isb360]

Question: Why do you want them disconnected after start-up?



Anything that can help warm the engine quicker seems like a benefit to me. Especially when it's chilly outside. Also, the more time it takes to warm the truck, the longer your fuel economy will suffer.

 

[Tomscreek]

Why do you want them disconnected after start-up?

After engine is running, the heaters are not needed. It's just part of the emissions BS and a waste of juice. I just want to put a manual switch in the cab to disable the grid heaters.

 

[ACoyle]

I recall that hvac suggested this a few years ago, therefore, I think that it has been around for a while.



I also recall a few threads that stated that it was for emissions.



I think the grids pull something like 120 amps, quite a knock.



I have not heard of the computers getting crankey.



AC

 

[isb360]

Does it increase the life of the heaters or relays or has it been proven to increase the life of the alternator/charging system? I am curious because off hand I can't think of another use for all the current they are drawing, except that the load on the alternator will incrementally load the engine a bit, possibly helping warm it up?



Sorry, just engineering skepticism, but what's the point?



Tim

 

[CToney]

Relays are only good for 50,000 cycles so, the less they cycle the better. Up here in Canada our colder weather reduces the life of the relays and the charging system. Batteries and the brushes in the alternators just don't last as long. Once the engine is running I don't think I they need to run. The heat they put out won't make the truck warm up any quicker. You have to drive it to create enough load and heat. If my truck smokes a bit doesn't really bother me because I live on a farm and there is no one to get upset at a little smoke. Dealerships want $250 for new relays up here.



Hope this explains where I'm coming from.

 

[isb360]

that makes a lot of sense. Hadn't looked at it like that before. Thx for the explanation.



Tim

 

[WTBurke]

I believe once the vehicle reaches 15mph the system no longer cycles the grids. Also, at one time Practical Solutions out of Helena MT. had a kit for this but, I understand they are no longer in business. It's quite simple to disable the DC for the relays to prevent them from closing however; I believe it throws a code but, it is of no consequence.



Just food for thought

William

 

[Jim Fulmer]

The relays are disabled at 25 MPH! Although relays may go out they can be replaced cheap, I had to do mine also as my motor didn't like starting cold that much.



http://www.tdr1.com/forums/showthread.php?t=124484&highlight=grid+heaters+relay



Mark puts out some good info in this thread.



Jim