Horn not working - restarting ignition always resolves

Stocho

Active Member
Joined
Jul 4, 2009
Messages
335
Hi

The car is E300TD 1998.

Had this problem for a while. My horn quite often does not work. "Hummering" it etc does not work. But what always resolves it is switching ignition off then on. So the actual horns are OK, so is clockwork spring as it is hard to imagine how switching ignition off and then on again would fix it even temprarily. I did replace a relay in the fuse box. What else could it be? I have suspicion there is a circuit to switch off horn when car is being started - may be that circuit activates when it should not?

The other problem I noticed is that sometimes the message indicating bulb failure appears but actual bulbs are OK.

The other problem I had in the past but that resolved itself was with air heater in winter. It was just non responsive sometimes to tempreture changes on the controls. I had that for two years and then it fixed itself. No problem now but may be Horn is a related problem somehow.
 
OP
OP
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Stocho

Active Member
Joined
Jul 4, 2009
Messages
335
Hi

Based on no repplies I suppose my problem is very unusual. I have some additional information that might help others to help me...

When driving the car pressing up and down on the key (not rotating it, by up and down I mean not in and out but with force applied perpendicular to the biggest surface of the key) makes kind of relay- like noise.

If horn is not working it is sufficient to do that to make it work again. So looks like the problem is ignition key / socket related but strangely does not affect anything else apart from the horn!

Any ideas on what and why could be causing it?
 

trapperjohn

MB Enthusiast
Joined
Nov 19, 2008
Messages
7,305
Location
Lancashire
Car
124 300D 24V Estate
Perhaps the "cowl" around the key needs tightening a little. There must be something on the forum somewhere about how to change the EIS (Electronic Ignition Switch)

Mind how you go though a new switch is around 600plus quid.
 

dave e320

Active Member
Joined
Nov 22, 2008
Messages
70
Location
kent
Car
mercedes e 320 avantgard
horn not working

:thumb::thumb::thumb::thumb::thumb::thumb:
Hi

Based on no repplies I suppose my problem is very unusual. I have some additional information that might help others to help me...

When driving the car pressing up and down on the key (not rotating it, by up and down I mean not in and out but with force applied perpendicular to the biggest surface of the key) makes kind of relay- like noise.

If horn is not working it is sufficient to do that to make it work again. So looks like the problem is ignition key / socket related but strangely does not affect anything else apart from the horn!

Any ideas on what and why could be causing it?
it is the eis barrel? this has just been sorted on my e320 1999 by a1 merc of leyton at a cost of £540.00 it was starting to break down internaly causing the horn to stop working and the sunroof to not work at all. a big thank you to a1 merc for sorting this out when an auto electrician and merc dealers failed to act.
 

vijilants

MB Enthusiast
Joined
Jan 23, 2007
Messages
2,319
Location
London
Car
W205 C43 AMG
The symptoms point towards the EIS is failing and as they charged you £500 + id say that they replaced the EIS.
 

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