Heated Seat/ Rear Defrost with 2-way

you need to figure out what kind of trigger both the switches need, if a (-)negative trigger pulse turns the seats and the rear defogger on then diode isolate the lock wire and program it to lock after start up. this will provide the trigger, i suggest you use a relay to boost the output, 200milliamps isn't sufficient. now if it is a (+)positive trigger you can do it the same way exept now you need to isolate it from the switch completely so you don't burn the switch out. i think that the seats should be able to be triggered but the rear defrost could be tricky. good luck, i hope i helped out a bit.sweet.

i forgot to mention that you will need one or more latching relays thats what is going to supply the output while whe truck runs, otherwise it will only be a pulse.sweet.

I hooked up the heated seats on my 04 tahoe through an auxiliary that gives a 250 ma (-) pulse. I had to reverse the polarity and send the wire directly to the switch module (not the standard door module but the module that has the heated seat switch in it). If you figure out the mirrors and rear defrost, please let me know. I want to do it on my Tahoe too.You can do it!

Oh yeah, the reason I picked up the wire directly at the switch is because the switch on the Tahoe only sent out a + pulse. I didn't have to use a latching relay to keep current flowing. Anyway, I can't imagine the Avalanche and Tahoe being different on the heated seat switch.You can do it!