grid heater reprogramming

I've heard some TDR members talk about reprogramming their grid-heater's so they turn on at a lower temperature. I just ran to Home-D and it's 60 degree's out (cold engine /first time started today) and the grid heater was cycling as if it was 'cold-out'. How do I reprogram my GH's so they don't turn on unless it's below freezing outside?

 

I would leave it alone. The puter turns on the grids for various reasons, including the good of the engine and/or the environment.
And it isn't hurting anything be cycling.

 

You can put them on a switch. When the switch is off they won’t come on. When the switch is on, they’ll operate as normal. At least they would on my ‘98. Your 3rd Gen may throw a code.

 

It will throw a code if the puter senses the coil in the relay is open. ( intake Air Heater Relay High)

 

Figures.

 

I don't think you can reprogram but as mentioned add a switch and deal with the possible code appearance. However iirc it is triggered by temp cant remember if it is the battery temp sensor or the iat sensor that it is getting its temp signal from for the grids. Could be one or the other is getting wonky or just enough degradation in the wiring of the circuit for it to get incorrect readings.

 

Could be the sensor, cant remember if it is the battery temp sensor or the IAT sensor that gives the temp input for the grids to the ecm. Could also be degraded wiring for the appropriate circuit that is causing it to get a bad signal from the sensor

 

There is no Code as long as the relay keep working and only the feed line is interrupted. BTDT

 

What do you mean by "feed line"? is that the high current connection? If so then yes, you could disconnect that.

 

I forget, is it the grid heater indicator that comes on if there excessive injector return?

 

Yes that's the one.
I disconnected it once years ago on our winter tour to the polar circle when my batterys get suddenly weak.
No codes for 2 weeks till I got new batterys.

 

That should work. The puter is only looking for the resistance of the coil in the relay. As long as that's present, it's happy.

 

With UDC Pro tuning on a Touch or MM3 the grid heater can be adjusted. I do it on every custom tune I write.

 

A couple decades or so ago there was a guy by the name of Harold or Harvey (cant remember) who built in his garage, and sold through the diesel forums, a wiring device he called the "grid heater saver", which disabled the grid heaters when the engine coolant was above set coolant temperature. It prevented the constant re-cycling of the grid heaters when you're making frequent stops around town driving where you're shutting the motor off and re-start the engine.
I've tried to find out if anyone has one to possibly replicate, because the Harold/Harvey guy is nowhere to be found anymore...

 

There had to be more to it that ECT. The grids fire based on intake manifold temp. On a warm engine the IAT goes up when you shut it off running errands, not down. That makes the grids less likely to be used for in town driving, even in cold cold weather.

 

Well since he's MIA.....I guess we'll never know.

 

On my 04.5, I took my grid block out (deleted) & insulated the heavy wires & no codes.
Wanted to see how much it helps, starts fine w/a lil more cold start haze & a lil more crank/sputter at 25*

 

This sounds like one is trying to fix a problem that doesn't exist. There are possibly millions of trucks running around with grid heaters turning on when the ECM thinks they should.