Need Help - Grid Heater Issue

[Georgiaboy]

So my grid heater is not engaging.

I have my edge insight and can see the IAT temps, and they don't go up fast like I've seen on some videos when it works.

Thanks for helping, guys.

Troubleshooting done:
The grid heater light comes on at pre-start with no codes.
I don't see a power drop when starting.
Remote starts with no issue.
New OEM relay.
Power is verified to relay.
The ground is good to little wire on the relay.
Another little wire, when unplugged, throws a P0542 code.
So it's got some info going to it, I assume.
Test light between positive relay post and post going to the grid with no power.

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[AK Bob]

I see from your previous posts that you are using the screw-in heater on a Banks intake horn and running EFI Live tunes; not sure what year model truck you have.

The grid heater circuit is quite simple; see the diagram attached.

You have already determined that post 30 on the new relay has battery voltage available. As a test, I would remove the small wires 85 and 86 from the relay, then ground the relay post 86 and apply battery positive to post 85.

Do this momentarily while checking for battery voltage at post 87.

If you have a battery voltage at 87, you know the new relay is working, then check for current flow in the A122 wire.

If you don't have a current flow, you either have an open heater or an open A122 wire.

Grid Heater Circuit.jpg

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[Corkey]

Who needs Alexa when you have Bob?

Good info!

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[watersupply189]

Who needs Alexa when you have Bob?

Good info!

Bob Quest is similar to map quest!

That is excellent info.


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[Georgiaboy]

So I did what you said, and the relay actuated.

So the relay is good, which I had hoped for since brand new.

So it has to be the 85 or 86 wire, but 85 throws a code if unplugged momentarily.

86 I tested for ground and good.

I was told tuning couldn't turn off the grid heater, so it's not because of my new tune, right?

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[AK Bob]

So I did what you said, and the relay actuated.

So the relay is good, which I had hoped for since brand new.

So it has to be the 85 or 86 wire, but 85 throws a code if unplugged momentarily.

86 I tested for ground and good.

I was told tuning couldn't turn off the grid heater, so it's not because of my new tune, right?

If you don't see battery voltage on pin 85 of the relay when the PCM commands the grid heater, you either have an open in the wire from the PCM to 85, or the PCM is not supplying the voltage because it's defective or has been turned off by tuning.

Edit:
Since removing the 85 wire from the relay/solenoid gives you a trouble code, you don’t have an open between the PCM and 85.

If the temperature conditions exist for the grid heater to turn on and you don’t see the 12V on 85, then either your tuning has turned this function off, or your PCM is not providing the voltage.

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[Georgiaboy]

I am posting here to help all and my new buddy AK Bob.

So my tuner guy says the grid heater can't be turned off in EFI Live.

I took off the wire from the relay to the grid heater yesterday.

I remotely started it this am and this early afternoon before the temps got above 59 here in good ole Georgia.

I randomly checked my edge for codes, and what do you know, P2609.

So the system does see the grid heater removed.

I'm even more confused now.

Because I don't see on my IAT temps zooming to 100F like some Youtube videos.

So I think the grid heater is not working, and after all my tests, everything else is good except the 12v from PCM.

I will double-check that one next cold day we have and re-verify that it is or isn't sending 12v.

I will ask the tuner to add P0542 and P2609 to the forget list if I use or don't use the grid heater.

I will keep you posted.

Thanks all.

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[AK Bob]

I am posting here to help all and my new buddy AK Bob.

So my tuner guy says the grid heater can't be turned off in EFI Live.

I took off the wire from the relay to the grid heater yesterday.

I remotely started it this am and this early afternoon before the temps got above 59 here in good ole Georgia.

I randomly checked my edge for codes, and what do you know, P2609.

So the system does see the grid heater removed.

I'm even more confused now.

Because I don't see on my IAT temps zooming to 100F like some Youtube videos.

So I think the grid heater is not working, and after all my tests, everything else is good except the 12v from PCM.

I will double-check that one next cold day we have and re-verify that it is or isn't sending 12v.

I will ask the tuner to add P0542 and P2609 to the forget list if I use or don't use the grid heater.

I will keep you posted.

Thanks all.

The fact that you are getting the P0542 code with the power wire to the heater removed tells me that the PCM was previously seeing a voltage drop from the grid heater, and so post 85 did previously receive 12 V.

I have attached the troubleshooting information on both codes for anyone interested.

I have no idea about heat output from the screw-in heat element compared to the stock heater.

The stock heater draws 223A; it would be interesting to compare this with the amp draw of the screw-in element.

3D1A5083-D9C6-4FA9-84CB-FDFC997C73DA.jpg

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