Speedo / Stereo Conflict???

[simyc1]

Is this an earthing problem???

Driving along in my automobile....
look down and haven't got a clue what speed i'm doing.....
only one way to find out........
turn on the stereo

No No No the radio presenter doesn't announce my speed ....
No No No I haven't got the car hooked up to the Police CB network.
Seriously just a regular stereo on a regular C180, any ideas how to have it work properly??

Thing is I've recently had the stereo out working on replacing the heater panel, and decided to re-connect up a green n white lead which fed the stereo that had been cut, putting 2 n 2 together I'm guessing this is the cause, but surely this shouldn't happen.
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[Stratman]

The only thing I can think of is that the cut wire is a speed signal to tell the radio to go louder when your speed increases, and that it's somehow loading the speedo.

 

[simyc1]

Very True

Funny was speaking to a Merc Employed Mechanic, after my fuel pump seized (Bad Petrol, £20 off ebay and running perfect again) anyway, he told me basically the same.

Theres a short in my stereo, or a wire has been crossed so that when the stereos turned off, the speedo gets kicked off too, turn on the stereo and hey presto.

Now i've only had the car 3mths, and as i've been working on the heater the stereos been in and out, and true enough theres was until I reconnected it a cut wire on the stereo.

So was I sold a dud... still not bothered love the car (aka the Beast) and i'm gonna drive it til it drops, so if the mileage doesn't increase.... what the hay! PS don't tell anyone incase I do decide to flog it ha ha, no seriously what a reasonable amount of miles to do each year??