Another stupid grid heater post

I hate to even bring up the topic of grid heaters.. truck was starting hard once winter hit, and I realized (bought the truck in may) that the grid heater isn't working. I tested the fusable link from the battery to the relay, and had power, but didn't have power coming out of the relay. I replaced the relay tonight , and had the same issue, no power coming out.

Seems to me like the ecm isn't telling the relay to activate. Could this be the Intake air temp sensor? With my 'wait to start' light activating in the dash, I assumed the IAT is good

Any helps appreciated

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I'm in the exact same boat with my 2wd truck. power to the new relay but nothing coming out and my wait to start light comes on. I tested the trigger wires and I get 12v when the wait to start light is on but on the ground wire I get 60ohms. I don't think this is a good enough ground to pull the relay in but I could be wrong.im all ears

To test the solenoid, I can just use a hot and ground run off the battery to the trigger posts on the solenoid , and see if the grid heater activates, right? Essentially the sane thing you'd do to make a manual switch right? Ground the solenoid , then use a toggle in the cab

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Yes you can test that way or just wire them manually, which ever you prefer.

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You both refer to the "relay" in the singular, there are two of them, one for each grid heater. Are you looking at the right component? The PCM sends a ground signal to the trigger wire, the hot triggers are always hot. The factory service manual explains how they operate.

Yes, we are talking about the correct part

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I just toyed around with these old relays for the last couple mins, which both were still good. I grabbed a multimeter and tested a set of trigger wires, and upon turning the ignition I only saw .5v from the trigger wires.

Leaning towards the manual switch option at the moment, ratger than chasing electrical in the middle of a snow storm

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I have mine operating from a toggle switch in the cab. The hot trigger wires have not been messed with. I disconnected the ground wires and ran a single ground wire that attaches to both relay poles into the cab to the toggle. The other pole of the toggle is wired to a ground on the dash.