Fuses! - W124 1991 500E


Active Member
Sep 15, 2007
Lincoln UK
500E & RS4 B7
Attention all 500E/E500 owners, I know theres not many but bit of advice on fuses.

Replaced all my bulet fuses today with new ones all round and noticed the following:

Here is a picture of the fuse box and surround Auxillary fuse boxes:

View attachment 11845

In the owners manual it states that there should be no fuse in slot 11, which is the case, (Pink Circle in pic)

View attachment 11844

It also states that there should be no fuse in slot D. But there is a Red 16A (Red circle in pic). Fuse slot D is for auxillary fan but in manual says E 420, E 500 Fuse not occupied!

It also quotes there being next to the main fuse box,
"Auxillary Fuse Boxes"

Fuse 30 A
E 420, E 500 - Fuse 25 A (blue) Blower motor (vehicles with automatic climate control)

Fuse 16 A (red) seat heater, front, permanent current for trailer
E 420, E 500 - Auxillary Fan

.....is this the said box? and if so there should be a blue fuse! No? My car def has auto climate control

View attachment 11846

Any advice here would be appreciatted

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MB Master
Jun 22, 2003
Perth, Scotland
W204 C200CDI Estate
there are 2 possible control set ups for the A/C auxiliary fans around that time
One uses a combination relay K9/ki/k2 which has an external 30A supply fuse. This is probably the "unused " blue fuse in the auxilliary fuse holder. The other setup uses 2 distinct relays K9 and K10 which are internally fused and there is no external Fuse . It sounds as if that's the setup you have. Since you are having trouble with your aircon auxilliary fans it might be worth checking/replacing these relays? relays B and C here AFAIK

This is just an educated guess so proceed slowly and check your voltages carefully.
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