heated seat, drivers side, goes crazy..

[Duraswede]

Hi!
My truck has been running without any trouble a couple of months now, but it did'nt last longer than that... yesterday the heating in my seat was making its own rules, it turned on automatically on level 3, it was the first day this fall that was below freezing, so i thought that it has some automatic-feature, but after a while it started to burn my ass, so i tried to turn it down, but nothing happened when i pushed the buttons, so i pulled over and turned off the engine and restarted, then it was off, and again after some seconds it turned on again, but now on level 2, and i was able to turn it off, but it suddenly came on again after a while???
i looked for a fuse to pull and found one that is called IGN3, it was for the heated seats, so i pulled it and i was very surprised about that the heating worked as it should, i could turn on&off and change levels just as it should be, without the fuse!

i have connected my Pyro-gauge on the same fuse, just a tap behind the fuse box, but i doubt it could be the fault, and it has always worked before, the gauge has been there for over a month now..

so is there anybody with the same problem??
i would be glad to hear your thoughts about this..

[DmaxMaverick]

The heated seats are routed through the BCM.

The circuit could be getting some feedback from the pyro amp. If it is coming on and not responding, it could be sending the interference to the BCM, and that could be a real bad thing (like it could fry the BCM). I suggest moving your power tap. I normally use the power window circuit for this. It is heavy enough, and has a circuit breaker. An added bonus is, it is on the RAP circuit, and not on the BCM (RAP is relayed from the BCM, so no feedback). Meaning, it will stay on until you open the door or it times out, just like the radio and windows.

[Duraswede]

The heated seats are routed through the BCM.

The circuit could be getting some feedback from the pyro amp. If it is coming on and not responding, it could be sending the interference to the BCM, and that could be a real bad thing (like it could fry the BCM). I suggest moving your power tap. I normally use the power window circuit for this. It is heavy enough, and has a circuit breaker. An added bonus is, it is on the RAP circuit, and not on the BCM (RAP is relayed from the BCM, so no feedback). Meaning, it will stay on until you open the door or it times out, just like the radio and windows.
Ok, thanks
i'll try to just cut the power wire to the pyro and see if it works then, what confuses me is that i had the pyro installed for over a month and it has worked until now...
When i installed the pyrometer i just checked for a fuse that was hot when the ign. was on, and found this one, it was 10amp so i thought it would be perfect for a gauge, if i tap into the window circuit, which is around 30-40 amp it will be necessary to use a smaller fuse on the cable to the pyro gauge..

it was also strange that the heating worked perfect when the fuse was pulled!!! the owners manual clearly stated that this fuse was for the heated seats..

[DmaxMaverick]

I can only guess, but it sounds like the "stray voltage" interfering with your seat heater with the fuse in, is powering the circuit with it pulled. All the more reason to abandon the circuit for the pyro. It's really hard to tell with the 2003+ multiplexed electrical control system.

The pyro amplifier lead should have its own inline fuse, in any case. 1 or 2 amps, IIRC. Even on a 10 amp circuit, it's too much for the amplifier, and it should have its own fuse.