RE: Seat heaters

[New England: July-August & winter 11-Nov-1994 0845 <samaras@wrksys.enet.dec.com>]

I have an 86 5000CS TQ.  I've repaired the heated seat (driver side) 4 times.
There are two failure modes:

1. There is a little thermistor (temp sensor) buried in/under the heating pad.
The wires tend to break off. This happened once, and I resoldered it. It never
broke again. Getting to this thing is brain surgery. The first time, I removed
the seat from the car, but that is not necessary. You need to do some cutting,
re-gluing, and re-stitching. I don't have time to write it in here at the
moment...

2. The heating element opens. This is as about as much work as fixing the temp
sensor. Finding the open wire can be tricky.  No need to buy the replacement
pad.  The wires are nichrome and cannot be soldered. I just twisted them and
sealed with a drop of super glue.  On average, the fix lasts 1-1/2 years.
Again, getting to the element requires some skill. All the "opens" I've seen
are at the middle left area of the drivers seat.

Retrofitting the heaters into non-heated seats would be an _awful_ job. The
seat back, the seat bottom, and the seat sides all have elements in them. 
They are wired in series. You would have to completely disassemble and
un-upholster the seat.  THEN, you'd have to make sure the wiring is there and
the controller electronics are installed in your car.  
Cars that had heated seats as an option may already have the wiring in there
as well as the controller sockets in the relay panel. If this is your case, I'd
go to a junkyard and buy the heated seats and the controller stuff.  

I know it sounds like this is an easy "heating pad" add-on, but after working
on mine, I'd never attempt to install elements in un-heated seats.

Good luck,
...bill

DEC
Maynard, MA
508-493-7322