So I'm working on wiring heated seats into my 300D 2.5. See the picture below for reference, so you can understand my question:

A) is the accessory connector block - the OE heated seat wiring harness plugs in here (I don't think it matters where - ther are a number of empty slots, I just chose one at random).

B) is what my question is - we'll get to that in a sec.

C) is 12V power - I think this goes to the auxiliary fuse box in the engine compartment.

D) is the heated seat wiring harness.

Note that the heated seat wiring harness was added by me, and what I found when I looked under the kick panel was B connected to C. Now, when I was looking at info on the heated seat retrofit, I read that I would have to add the accessory fuse box and wire in the 12V power source to the footwell. But when I looked under the hood, I found the fuse box in place, with an 8A fuse in position one and position two empty.

Looking at the FSM, the 8A fuse appears to be for something called "CETL transmitter/receiver," but I don't know what that is - some sort of phone connection or something? (EDIT: Actually, I think CETL is a typo, because the FSM also uses the term "CTEL," so likely a phone thing - although my car does not have a phone receiver or anything - maybe just pre-wired?). The problem is, that's only supposed to be for MY93+, and my car is a MY92.

I guess my question is, can I just leave B unplugged? Will I be losing anything important? Or, better still, is there some sort of Y-splitter that would allow me to connect both B & D to C?

__________________

You can verify if C goes to the aux fuse box by checking for +12v, then pulling the fuse and seeing if the voltage goes to zero. If so, that mystery is solved.

CETL is likely the cellular telephone wiring, which may have happened on some 1992 models (it was a dealer-installed option, where the dealer added the phone components to the existing factory pre-wiring). My guess is your car was pre-wired for the phone and that connector B may be for that system. If everything else in the car works ok with B unplugged, I'd call it good enough!

__________________
Check out my website photos, documents, and movies!

Thanks for the info. I know the 12V line is drawing power because I can get the switches to light, and I can hear the relay in the back clicking when it does whatever it does. As for feeling heat - well, it was pretty subtle, and not as quick as the seat heaters on my newer vehicles. So far I only have the passenger side hooked up, and it was a short tes - hopefully it'll be more impressive in actual practice.

__________________

The bun warmers are slow to warm up... in winter, you'll likely run them on high for 2 or 3 five-minute cycles. Much slower than newer cars which heat up quickly. Still beats cold seats though!