This is making me crazy...but now we noticed, if we push the button for the heated seats before the truck is started ( while waiting for the coil light to turn off)

when the trucks starts...the engine light comes on, throwing a " grid heater malfunction" code.

Obviously this is a wiring/electrical problem....What the heck is wrong here???

Dealer is clueless still...

 

just wait to turn your heated seat on till after the truck is started. when you start the truck it turns off your heated seat anyways, at least mine does

 

^it shouldnt throw a code..there is something wrong.

Also I have been through 3 grid heaters now. There is some short or electrical problem somewhere...

 

Mine does some strange things also. If I start the truck, then turn on the heated seats and start to drive away I hear a chime, the radio station changes and the heated seats turn off. I used to think it had something to do with the automatic door locking feature so I would lock the doors manually before driving off but it still does it.

 

^ thats spooky LOL!

The dealership is looking into things. I have had a never ending engine light being one always a gride heater code. They have changed wiring, heaters, ground wires etc and still happens. Everything I find about faulty grid heaters...is all electrical errors and not the actual heater itself. I think its a fluke electrical error...

 

My seat heater won't turn on until truck is started.

 

How exactly does the heater fail?

The only method I can think of is that it actually burns up from being left on too long. I don't even know if thats possible but its really the only method I can think of.

I've read that they draw over 200 amps at 12V. Now as we all know the system will not maintain 12V during this cycle so the figures will change but at any rate the current is really a lot more than the cable can handle continuously. All conductors can take a lot more current than they're rated for for a short period of time. I believe thats one of the reasons the grids cycle. The grid heater its self may also not be able to tolerate being continuously on.

If thats the case its a control problem, nothing with wiring and such.

Basically the grid heaters are controlled by a relay. The ECM controls the relay. If there is any problem I would certainly suspect the ECM. The hardparts feeding the grids don't have very many failure modes.

Have they looked into changing the ECM? With all the other freaky stuff your truck is doing I would certainly consider it.

 

try this for me , i think it will stop the cel and if it does i can help trouble shoot it further, there is a 160 amp fuse link from the + battery lead to the grid heater relay, take it off the battery bolt i think it is a 7/16 wrench ,and drive it for a couple of days and let me know if this works