A/C on = NO HORN. Why?
 

Its been HOT here!
The past couple of weeks have been 100 degrees and up!
Needless to say ive been utilizing my ice cold A/C in the 300DT over the duration of this heat wave. However, there have been times recently when ive needed to use my horn to signal my presence for unattentive drivers- but when my A/C is on my horn doesnt work! I can sometimes get a faint wimpy beep, but 98% of thhe time I can lean on the horn as hard as I want and I get nothing. If I switch the A/C off the horn works fine. Ive noticed this has been a problem on all 3 of the w123's I have owned so im sure im not the only one who has experienced this odd behaivior.

Anybody know why it does this?

Humm, I don't have A/C so I cant help much. You could check the wiring diagrams ound online and in the Haynes/Chiltons manuals to see if there is a relation in circut.

I do know of a cruel trick to play with a good friend if you work on their car... ;)

Be sneaky, swap the A/C clutch power line with the horn wire. After they leave the shop and turn on their A/C the horn will blare! :D It will take a few seconds before they put 2&2 together. Kind of cruel, but VERY funny. :)