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1995 E320 Wagon
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73 Posts
Discussion Starter #1
Hi All,

trying to sort my power antenna. I've searched high and low, but can't find any info on wiring going into the power antenna unit, or at least how the trigger cable (blue) behaves.

My antenna unit is shot and I just pulled another one from a donor car.

The plug in the rear has 4 cables - Brown, greyish, red, blue.
I have no idea what the greyish one does.

I hooked up a multi-meter and the red is + and the Brown is -. I'm getting 12 volts.

Then when I place the + on the red and then - on the blue (trigger wire) I get the following. 12 volts when the radio is off and 0 volts when the radio is on.

I hooked up both power antenna units and neither of them do anything when I turn it on and off. Any ideas for trouble shooting or at least what i should be getting from those 4 wires when I turn the radio on and off?

thanks,
dave
 

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1995 E320 Wagon
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73 Posts
Discussion Starter #3
I found all those - i just don't understand how to test the connector in the trunk.

if i hook up a mulit-meter to the 4-prong, what should I see when i turn on/off the radio?

I don't understand the diagrams that well, except for that the brown is a ground, the red is the pos, and the grey is for the cell phone or something, and the blue . . . .what does the blue do? does it get a ground? What type of signal do I test for?
 

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2007 E220CDI, 1990 300E-24V, 1987 W124 3.6 AMG build 1993 E500 W124, 94 320CE, 1997 W140 S280
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The blue wire is the 'trigger' wire for the antenna to raise up.

In my 500E I only use the brown, Red & Blue wire to operate the power antenna.

IIRC you can simply touch / jumper the Blue wire to the red on the antenna (As a test only) and that should make the Antenna rise as you keep it connected. And as soon as power is dropped from the blue cable the antenna should retract itself again.

Try that test first. If the Antenna you have operates fine in this manner then pull the radio & make sure the wiring is OK back there. If the head unit has been changed then it is likely the wiring has been altered behind the radio & may not be correct.

So you should see-

Constant Earth on brown wire
Constant + Live on Red Wire
+ Live on Blue wire when the Radio is turned on only. This should turn off the instant the Radio is turned off.
 

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1995 E320 Wagon
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73 Posts
Discussion Starter #5
as of now when i test it.

if i hold my multimeter to red and brown i get 12v

if i hold my multimeter to the red and blue when the radio is off i get 12v
if I hold my multimeter to the red and blue when the radio is on i get 0v

what you're saying is grab a paper cliip and jump the blue to red and the antenna shoudl go up?
 

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2007 E220CDI, 1990 300E-24V, 1987 W124 3.6 AMG build 1993 E500 W124, 94 320CE, 1997 W140 S280
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1,309 Posts
To detect voltage one wire must be on an earth.

So testing for voltage between blue & red won't tell you anything.

What you should test is this-

Ground one wire of the multimeter to the brown wire (use the black probe of your multimeter) Then connect to the blue wire with the radio off (using the red probe of your multimeter) This should be zero voltage.

Then put the radio on & observe the reading. It should jump to +12v (or battery voltage)

If this test works then it seems your antenna may be defective. Is the replacement unit new or used?
 

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1995 E320 Wagon
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73 Posts
Discussion Starter #8
ok - now we're getting somewhere.

i jumped the wire and then antenna went up. unfortunately i learned that the one i bought is nasty inside - the second stage of the antenna is all corroded. Back to the place I got it from . . .

now . . why is my head unit not sending the +12 on the blue when it turns on . . . ?
 

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2007 E220CDI, 1990 300E-24V, 1987 W124 3.6 AMG build 1993 E500 W124, 94 320CE, 1997 W140 S280
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1,309 Posts
You will need to pull the radio head unit & check the wiring. Someone might have left that trigger wire disconnected in the past
 

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1995 E320 Wagon
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73 Posts
Discussion Starter #10
thanks man - i've got a wagon and I feel like getting that new version to work involves some cutting and mods . . .

first i'm going to try and return this unit to the guy i got it from.

next i'm going to take out the head unit and check where the blue comes out if i get 12v - figure out if the issue is at the becker. if that's the case, then i need to send out maybe.

thanks man for all your help!
 

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1995 E320 Wagon
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73 Posts
Discussion Starter #11
i pulled it last night - the trigger wire was firmly in there - will test with my multimeter and see what's up.

thanks for all your help!

-dd
 

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2007 E220CDI, 1990 300E-24V, 1987 W124 3.6 AMG build 1993 E500 W124, 94 320CE, 1997 W140 S280
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No problem.

Do make sure the trigger wire is in the correct place on the head unit. (By checking the Becker install details- pin outs)

Keep us updated with how you get on
 

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1995 E320 Wagon
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Discussion Starter #13
I jumped the wire on the antenna and got it to go up - unfortuantely the used antenna is in rough shape. going to return it.

So . . . my old antenna is going to becker in NJ and i'm sending the head unit. the front dash speakers sound bad so i brought them to a local speaker guy. $30 if it's just the foam, $50 if he has to wrap the coils. figure it's cheaper than new speakers and better then cutting out to make aftermarket speakers work.

will keep you all posted.

-dd
 

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1993 300CE Cabriolet (mine) ; 1994 E320 Wagon (wife's) ; 1990 Benz 300E 2.6 (son's)
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6,752 Posts
google 'carpower crb-120pp', they are available from a site in the Netherlands for a quite reasonable price and fit directly into the front dash places... you just need to splice the wires supplied with the CRBs onto the connector plugs from the factory speakers. they are coaxial 2-way speakers, and sound better than the originals, and nearly as good as the $200+ Rainbow 120's.

ok, here, $37 a pair.
CRB-120PP*CarPower Pair of car chassis speakers 4Ω | Loudspeaker freaks

I've ordered from these guys a couple times, usually they just take a week or two.
 
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