Mercedes-Benz Forum banner
1 - 6 of 6 Posts

· Registered
14 Posts
Discussion Starter · #1 ·
My heaters dash pod has screwed up and won't shut the fan off when the key is shut off and removed.

Have checked both the under hood front fuse box and the rear trunk fuse box but can't seem to isolate the correct fuse to disable it.

Can any of you forum gurus help me to find it please.

I've temporarily pulled the battery terminal.

Thank you in advance.
Bryce Mack

· Registered
1998 S320LWB
834 Posts
It is not fused it has direct battery power. Your fan speed regulator is faulty and requires replacement. Don,t go cheap behr is oem get a made in Germany product. Not difficult to change but research it and do it right with thermal grease application. Good luck

· Premium Member
'99 S420 125K
1,863 Posts
I am experiencing 2 symptoms relating to a failure of this fan speed regulator.

On hot, hot summer days the fan speed would drop from high to low, then, after a few seconds return to high. It cycled like this every few minutes, sometimes for over an hour. This occurred quite often over this past summer(Florida).

On one cool winter evening, heater on, I noticed the fan remained on after the engine was off, key removed. The 1st time this occurred, at a restaurant stop for about 90 min, I was able to restart the vehicle, but I was startled by this unexpected incident. The 2nd time this happened, while changing the shocks absorbers, a few hours of service, it completely drained the battery.

My Indy said I should replace the blower and regulator at the same time, $1100, but it's NLA from MB, and the aftermarket products are not MB quality. Well...

I just ordered a Behr replacement regulator online for under $70, hoping this will solve the problem.

· Moderator
93 SL500, 95 SL320, 96 S320, 98 S500, 2002 E320 4Matic Wagon & A little 91 5.0 FORD Mustang
9,043 Posts
To all,

Our cars can no longer be repaired by the average mechanic as they will only replace large components.All our cars are restoration projects on ALL levels.

These climate control fans will get electrically noisy as they wear-out, and blow regulators. Possibly start drawing more operating current, so this stage it a it wise to put new brushes. The same applies to our alternators, so today's parts changing mechanics will not do that level of work as they want to give a petty warranty.

1 - 6 of 6 Posts