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Topic: Whats this switch do? Reply to Thread
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  Topic Review (Newest First)
07-06-2018 09:23 AM
lowesguy Interesting thanks!
07-05-2018 12:56 AM
robm.UK It's a momentary alarm switch, not a latching switch for a courtesy light.

If hood is opened while alarm is on, it triggers the alarm.

It is feasible to break into the car when it is locked by opening the hood and applying pressure to one of the vacuum lines, which pops the door locks. So MB fitted an alarm switch to protect this possible entry point.

I was told by an AA guy that this was the favoured way for the car thief on early models. Open hood; dispatch the under hood siren (if fitted); pop the locks; bypass the immobiliser (if fitted).

It looks like the early cars have this switch fitted regardless of whether the MB alarm option is fitted or not, so in some cases it could be regarded as redundant.

My '92 500SL was fitted with the MB alarm option, but the immobiliser was unreliable (intermittently couldn't start car!) so I fitted a Clifford alarm, which also utilises the switch.

While I removed the old MB alarm I found that the blue wire from the drivers door lock to the central locking pump in the trunk had been purposefully cut down by the seat, presumably as part of the original MB installation (?). In practical terms this meant that the drivers door latch would not operate the central locking until I reconnected this wire. Worth bearing this in mind if anyone has similar problem. Check continuity of blue wire between door latch switch and connector to pump in trunk. But I digress.
07-04-2018 10:22 PM
Originally Posted by lowesguy View Post
What is it? lighting? warning? I give up.
I believe you have a california model, then its the CARB diagnosis switch.
Cheers, Frank
07-04-2018 01:35 PM
lowesguy I put air horns and compressor on my old 56 packard, man you should have seen people move!
07-03-2018 01:56 PM
Originally Posted by 260e crusier View Post
A guy in a pickup blasted one of these a while ago in front of me in Ft. Myers. I just about shat myself. I wanted to pull him over to suggest he not use that in Ft. Myers - the average age is 85 and he could've caused heart attacks!
07-01-2018 09:12 PM
lowesguy I must have a rare model!
07-01-2018 07:30 PM
RKH Ask somebody to flip it while you stand 10-ft back
07-01-2018 06:20 PM
260e crusier
Originally Posted by lowesguy View Post
wish they had better horns on these once expensive cars!
Here you go :
07-01-2018 06:17 PM
260e crusier Is there a part # on it? If it's 1298210751, then it is for alarm.
07-01-2018 05:43 PM
lowesguy You mean my car has an alarm! Whoa! never heard it LOL, I don't see any under hood light. wish they had better horns on these once expensive cars!
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