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RE install of Becker Grand Prix - Help Plz

4K views 19 replies 8 participants last post by  redghost 
#1 ·
I have no manual, I did a google search as well as BW search for data on this question. This is a Becker 754 in a Gen I w126.

Allen had a nasty Pioneer head unit and a mess in the trunk. I now have that removed and am trying to install a nice Becker in its place. But the wires are sort of messed up.

The butcher of wires did label most of the wires so that he could tell what needed to be spliced to make the pioneer work. It took pix, but now my phone is bricked (always wait for some other idiot to upgrade OS before just doing it right away). I have been able to figure out the Antenna Amp wire (blue) but can not figure out which of the other four for the power part.

There is a dual wire set up, well there are two of these. Both have brown ground wires, one has a blue wire and the other a black wire as its pair. One of the pairings has the brown ground and a pair of yellow/black wires leading into what should be 12v. I know all the wires were attached to the old head unit, as I cut beyond the splices.

SO, which of these wires should be my RED and which the GREY, and then what is BLACK? and of the pair of brown, which should I choose as ground, or would I use both?

The other issue is where to hook up the Theft Stop wires? I have no more wires to hook to.
 
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#2 ·
Hello,

Rather than Gen I 126, it would be a lot easier for me if I knew the exact year & model car you are working with as the schematics do differ……..

Having that info makes it a snap to look up the correct diagram and pass it along.

The above is my own bias.. others may jump right in…

Good luck,

MBL
 
#5 ·
Allen is the car's name. 1982 300SD

radio is a becker 754

photos --
 

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#6 ·
I can sort of figure out the constant and switched (maybe) but which brown wants to be ground and what wants to be lights? I found the antenna wire and the antenna. If I can get the anti theft disabled, then all I need is the dealer to use his magic key to put the code.
 
#9 ·
It is what I could find for minimal cash that was close enough to make it seem right. This is a car I got FREE, so the less I need to invest the more ahead I feel.
I have head unit I snagged at Goodwill that is living in the SL waiting for the rebuilt Europa to go in. But that needs replacement of the console and replumbing all the console goodies like AC, CC, Fan and more.
 
#11 ·
I took a stab at it today. Somebody had mentioned I should use a multimeter to figure out where power was coming from. Turned out that the constant power was not there, but switched was. I had changed out the fuses when I got the car for new brass ones, but there were two spots without fuses then, so they got no new ones. Until today. Those fuses allowed me to find constant power, so I hooked up the wires as needed and now have power to the Becker. No wire to the illumination set, but it only needs a visit to the dealer for the key to make the dashes go away.

I have a number of Hirschmann antennas I am testing to see if they will extend. Figure I should install one that works and be able to have nice reception. If I get really lucky, I will hit the PnP and find a fader (the one in the SD is missing its wires) as well as the interior door latches so I can bolt the door pulls.
 
#12 ·
Took the SD to the dealer so they could use the Magic Becker key to unlock the radio. It took a few minutes to find out that the radio will not unlock. We tried it a few times to make sure the thing would not unlock. The dongle did its thing and made things happen on the LCD. When switched power was invoked, the thing would revert to four dashes.

Figure I will need to have it go to Becker for making better.

I did hit the PnP and got a few nice things. Antenna wire, speaker wire with original ends, speedo cluster, seat controls for Gen I, vac pump, Burl door trim, shift trim and console trim. Also the panel that goes on the rear of the cabin roof.

I got home and put the panel up, ran the antenna wire through the trunk to the cabin, then whipped out the sander and took a few moments to see if I could smooth the hell out of the perished clear coat on the flat surfaces. Hood, roof and trunk lid. I will need to see how the 100 grit did on the damage. Not sure I want to go all the way to bare metal before paint, but I can.
 
#14 ·
Turned out to be not very aggressive at all. It did smooth the clear a bit, and when pressed I was able to wear down seven coats of paint, but no bare metal. I will start a new thread on the restoration of paint for Allen.
 
#17 ·
I never said you were an idiot, just that I'm very surprised you got acceptable results using 100 grit on paint. That's what we use to strip peeling paint off of houses...

Your earlier posts seemed to indicate you were trying to repair the clear coat. Are you saying you used 100 grit for that purpose, or are you going to also repair the color under the clear? Or, am I the idiot?
 
#18 ·
I was not hinting that you thought I was an idiot, John. I am acknowledging that what I am trying to do may indicate mental defects. The horizontal surfaces are not going to fix, so I am effectively doing a repaint.
 
#19 ·
100 grit is going to put deep scratches and gouges in the metal after it eats through all the paint - I know you are trying to strip it quickly but don't use anything coarser then 220. I did a fiberglass toy go kart using 100 and put deep scratches in it that multiple coats of primer and paint could not fill


You'll be bondo-Ing the entire car if you score the surface with 100 grit
 
#20 ·
Thanks. I am pretty much done with 100 grit anyway.
 
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