The mystery of fuses 16 and 28

[youngbimmer]

I’ve struggled for over a year now baffled by why lumbar and heating would not work in my car. I was never brave enough to take my seat back off, and the PO assured me it worked when he had it. Arbitrarily today, I replaced fuses 16 and 28 while my climate control panel was removed, And low and behold, the fuses no longer tripped. What in the world? Lumbar works fine now. The back of my seat gets warm with the heated switch on, but not the seat bottom. Normal?

Without HVAC control panel, behavior defaults to defrost at medium speed.

[CamE32]

I'm pretty sure the bottom of the seat doesn't get warm. Mine doesn't - but it could be broken too I suppose...

EDIT: Mine does get warm on the bottom

[shogun]

Seat bottom also get's warm. Usually a broken wire in the seat bottom heater element. Here is a German instruction how to resolder the wire, translated with goodle, to remove the seat leather is on http://bmwe32.masscom.net/
Sitzheizung - Heizmatte reparieren !
Ausfall der Sitzheizung liegt oft an einem abgebrochenen Heizdraht an der Hauptstromversorgungsleitung die durch die Heizmatte führt. Die Heizdrähte sind daran angelötet und brechen direkt an dieser Stelle ab.
So kann man diese Reparieren :
- den Sitzbezug vom Schaumstoff abbauen
- um den defekten Anschluss zufinden beginnt man mit der folgenden Arbeit im mittleren Sitzfeld, da dort häufig der defekt Anschluss zu finden ist
- den Sitzbezug umdrehen und mit scharfen Messer (Cuter) den unteren Stoff und den eingelegten Filz an drei Seiten ca. 1cm von der Naht entfernt vorsichtig aufschneiden (aufpassen das man nicht die Sitzbezug verletzt)
- nun das eingeschnittene Stück umklappen und man sieht die Heizmatte mit den Heizdrähten und den Stromverbindungen die auf der weissen Heizmatte die als gelbliche FLecken erkennbar sind.
-- der gelbliche Fleck der einen schwarzen Brandfleck aufweisst ist der defekte Anschluss
- mit einem scharfen Messer die Oberfläche an diesem Anschluß durch schaben freilegen, den Heizdraht ein Stück abisolieren und erneut verlöten und ein Stück Leder als Druckschutz darunter legen
- mit Messgerät nun die Heizmattte auf Durchgang prüfen
- alles ok, dann das oder die aufgeschnittenen Felder mit Stopfgarn zusammen nähen ,das muss nicht schön sein sondern nur die Sache etwas halt geben.
- nun zusammen bauen und sich auf gespartes Geld und warmen Sitz freuen.

translation:

Seat heating - repair the heating mat!
Failure of the seat heater is often due to a broken heating wire on the main power supply line leading through the heating mat. The heating wires are soldered to it and break off directly at this point.
So you can fix this:
- remove the seat cover from the foam
- To find the defective connection you start with the following work in the middle seat field, as there is often the defective connection to find
- Turn the seat cover over and carefully cut the lower fabric and the felt on three sides with a sharp knife (cutter) about 1 cm from the seam (be careful not to break the seat cover)
- Now fold over the cut piece and you can see the heating mat with the heating wires and the power connections that are visible on the white heating mat as yellowish spots.
- the yellowish stain that has a black burn mark is the broken connection
- Scrape the surface of this connection with a sharp knife, strip the heating wire a little bit and solder it again, and put a piece of leather under it as pressure protection
- Now check the heating mat for continuity with the measuring device
- all ok, then sew the cut or the fields together with stuffing yarn, that does not have to be nice, but just give the thing something to hold together.
- Now assemble again and look forward to saving money and a warm seat.

or install aftermarket universal fit carbon heating mat http://www.7-forum.com/forum/showthr...ht=sitzheizung

Test the seat heater with seat belt buckled

[youngbimmer]

That doesn’t explain why my climate control panel was shorting out my seat heating, lumbar, and reverse mirror tilt. Very strange....

[shogun]

see the fuse details on page 0661-02 and -03
16
heated seats, also fuse 5
lumbar support, see also fuse 5
memory mirrors, also....
memory seat, also...

28
charging system, also fuse 17
e-box fan, also fuse 17
injection electronics, also....
servotronic
rear window defogger, also 21 and 46
windshield washer jet heater

check the 46 under rear seat and clean it! https://www.bimmerforums.com/forum/s...fire+rear+seat
https://www.bimmerforums.com/forum/s...ight=rear+seat