Fuse #21 blows as soon as the car is started - 1998 S420
 

Fuse #21 (20 Ampers) located in fuse panel located in the engine compartment near the brake fluid resevoir blows as soon as I start my 1998 S420. Some additional information that may be related as the following:

1. Fuse #21 blows every time I start the car. The things listed against that fuse are automatic climate control, outside mirrors heating, transmission oil cooler and heater wiper. I tried turning off the A/C and then replaced fuse #21 and re-started the car and that fuse still blows as soon as the car is started. I also disconnected the blower motor and blower regulator and started the car and fuse still blows. I try a 25A fuse (instead the 20A) and same problem.

2. The A/C fan is currently only running at one speed which is very low regardless of the settings inside the car. I have not replaced the blower regulator yet which is normally the source of this particular issue because I don't understand the issue with fuse #21 which keeps blowing.

I hope someone can help,

I could be the mirror heater. My 97 had some cracked insulation on the wiring in the mirror which shorted out. Gave me fits until it "smoked checked" one day.

Cheers,
Steve

I just want to share the solution to the problem in case someone else is having this issue. I changed the blower regulator and that fixed the air conditioning and the issue with fuse #21. The old regulator was faulty causing all these problems. Now the AC works great and fuse #21 is OK too.

Thanks Jorios for the update. I feel bad for the other guys who cried out for help and got no reply. and maybe still spending unnecessary money and time trying to figure it out.

Blower + regulator
 

Great advice post-- plastic cover panels at back of engine compartment are easily removed to get to blower. Less than $100 and less than 1 hr = repaired. Thanks for the tip