This info from the wiring harness in an '89 200TQ, the Coupe/90q 20V may
Two connectors to the heating element: BLK/YEL to BRN/BLU = 1ohm
Two connectors to the thermister that controls the preset: BLK/WHT to BRN/BLK
= 8.2k cold
Two connectors to the heating element: BLK/RED(x2) to BRN/BLU = 1ohm
Two connectors to the thermister that controls the preset: BLK/GRN to BRN/WHT
= 8.2k cold
Some people have successfully repaired bad heating elements with solder and
shrinkwrap or crimped connections at the burned out area, but you might
want to just replace the whole element with a new one (as described below)
if you don't feel confident with this type of repair.
The usual reason is a broken wire in the seat element. The elements are wired
in series, with a sensor in the seat element.
Remove the seat and separate the seat and backrest. The plastic trims that
cover the hinges are secured by plastic plugs that are pushed in flush with
the trims. Push them out from behind and the trim comes off, revealing the
clips that hold back and seat together. You have to take the connector to
pieces, among other things. Note down carefully where the wires go.
Remove the seat covers. You'll need pretty strong side cutters to deal with
the 'hog rings' that secure the cover to the steel wires passed through the
cushions. More of this later. Clear out all the fragments.
The replacement element (P/N 4A0 963 555 for the seat) goes inside the
cover. Lay the cover face down on a flat surface and lay the replacement
element on top. Note that the wires should come towards you - not towards
the seat cover surface. Otherwise you'll feel the lump when sitting on the
seat. You can see that you'll have to cut two slits with a very sharp knife
in the cloth backing of the seat cover to thread each arm of the element
through - it comes out the other end and the tab is folded over. You actually
cut through the cloth backing and the thin foam layer - the element slides
in right behind the old element, which stays in place. Don't even think about
removing it. When you replace the seat element (as opposed to the backrest
element) you still need the sensor in the old element. Cut the slits at 45
degrees - otherwise you'll get a small ridge in the seat when reassembled.
You need two tools for stretching the seat cover back on. You can use cable
ties, but the official way is much better.
The Hook. You find these in blister packs for picking seals (such as brake
piston seals) out of their hidey holes. Most such packs have at least
one strong hook with a plastic handle - sometimes they're double-ended. Or
you can make your own out of coat-hanger wire.
The "Hog Ring Pliers." Examples include Mark-Line 12108 pliers, Snap-On YA808
(not as expensive as most Snap-On stuff), and
Eastwood 52019 or 52032. You can
probably get a similar tool at an auto upholstery shop.
You also need a pack of hog rings--Audi's cheapest spare part. N 015 261
1 is around $13 for a pack of 100, or usually available from the same source
as the pliers.
Put the cushion on the frame, and start stretching the cover over it. Remember
where you cut off the old hog rings? The replacement procedure is to load
a ring into the pliers and hook the top of the 'C' shape into the seat cover
wire. Then get the hook and pick up the wire embedded in the cushion. Then
LUNGE - pull the seat wire up, at the same time as pushing down with the
pliers, and hook the seat wire into the bottom of the hog ring 'C'. Then,
with a smirk, just squeeze the pliers shut. Takes seconds with practice,
and produces a really tight seat. Pay especially close attention to how the
extreme rear of the seat feels when you sit on it, before you nail everything
down. Remember the fairytale about the princess and the pea?
See also: Leather Care, Seat
Heater Switch Bulbs
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