240d frying radio fuses - Page 4 - PeachParts Mercedes-Benz Forum

newtodiesel · #46 09-18-2010, 02:44 PM

Quote:

Originally Posted by micalk

According to the schematic...

1.5mm^2 Red wire => Switched Power (Fuse 4)
.75mm^2 Red wire => Hot at all times (Fuse 2)
.75 Blu w/ Red Stripe => Antenna / Amp signal (antenna relay or power sense for amp)
.75 Blk w/ Red Stripe => Illumination
1.0 Brn => Ground
.75 Blk w/ Red Stripe => LH Speaker
.75 Blk => LH Speaker Common
.75 Blk w/ Grn Stripe => RH Speaker
.75 Blk => RH Speaker Common

You'll need a light bulb or multimeter to test the diff between the similar color wires. You can use a 1.5 V battery to test the speakers, just a quick touch and you should hear the speakers react.

I agree regarding removing the fader, run front/rear wires to the fader and connect to the speakers where the fader sits if you want to retain the ability to revert the stereo setup.

here is the wire set up.

Yak · #47 09-18-2010, 03:51 PM

Quote:

Originally Posted by benzedrine

Ok..I dug farther back and found one more black plug! It has a Mercedes symbol on it. Maybe the original radio plug? Not sure.

Photo 1 is of the black plug. Going back a bit, it originates from the same sleeve as the ashtray wire.

Photo 2 shows what I think is the white ashtray plug on the left. From the ashtray plug the sleeve goes back up to the radio hole.

Photo 3 this is the end coming out of the radio hole. I believe the brown is ground and the red is the switched ignition.

Im so new at this its hard for me to tell what is original and what is not. If the black plug is the original radio plug, should I use that instead?

As always, Thanks for ANY help!

It's hard to tell exactly what photo 1 is, but I'd speculate that is the constant + red for the radio and the light gray for the rheostat "headlights on" setting for the radio.

Photo 2 is definitely the ashtray - radio tap. You can see the same thing here: http://www.peachparts.com/shopforum/attachments/car-audio-multimedia/72026d1252514193-keeps-blowing-fuse-little-help-radio-harness.pdf

Notice how the plug "upstream" is an exact copy of the plug downstream? Basically you're tapping into the cigarette lighter with that pigtail.

Photo 3 is more/less confirmation of photo 2.

Have you tried the ignition switch positions with the radio disconnected yet to verify there's not something else popping fuse 4?

benzedrine · #48 09-18-2010, 09:17 PM

Ok..got a multimeter and everything checked out. The red wire is switched. I did the ignition test and no blown fuses. So I went ahead and tried the new radio. No blown fuses! Not sure if it was the wiring or the old radio (both?) that caused the fuses to blow before. HUGE thanks!!!

micalk · #49 09-18-2010, 10:15 PM

Did you figure out what is the black two pin plug from post #39? The white plug should have been switched power for the radio, but the black plug is the kind that generally plugs into a switch or other item.

benzedrine · #50 09-18-2010, 11:31 PM

No, I never did. I did some searches to see if it was the original plug for the becker radio, but I wasn't able to find any photos to go by. Im definitely still curious though. I'll try to post a better photo- I didn't realize how blurry my first one was. Hopefully someone will recognize it.

Thanks again for your info. Im REAL happy to get the blown fuses resolved.

newtodiesel · #51 09-19-2010, 01:10 AM

Sorry I ran you off in the wrong direction...at least I got one plug right

micalk · #52 09-19-2010, 01:17 PM

What are the wire colors going to the black plug? It looks like one is red, but the other color is hard to tell. Red is generally 12V, use your multimeter to see if it is switched with the ignition or always hot. If yes to one of these, try pulling F2 and F4 to see if one of those control the voltage. Keep pulling fuses till the voltage goes away. That will at least narrow down the circuits. Based on its location it may have something to do with the radio.

micalk · #53 09-19-2010, 01:46 PM

The plug may be for illumination (grey wire with a violet stripe) and clock/memory (red) to the radio. I only have the schematic to go by, but these were connectorized together in one plug on the schematics for several models that I looked at.

Illumination is through Fuse 1 and is hot when lights are turned to parking or headlights. The radio doesn't 'dim' with the dimmer, that part of the circuit is for the other console lights and switch lights.

Memory is hot at all times through Fuse 2.

If this is the case, try to find another connector at a pik-n-pull for its mate and wire it up through that. Otherwise, cut the connector off and wire the radio directly. Your new radio may have an illumination input which you'll now be able to connect, and you can eliminate the blue wire to the battery.

Yak · #54 09-19-2010, 07:08 PM

For the screws for the ashtray mount (and in the spirit of the political season): I misremembered.

A one-half inch #10 pan head sheet metal screw ought to do just fine. It connects the metal frame into the plastic on the console. When I described it as a fine thread I was thinking of something else.

Also - I found a pic of the wiring (yeah, day late, dollar short...)

You can see there's a gray-violet and a red wire that are linked together in connector C173 - which could be the plug from pic 1. Going out of that connector the new colors that would mate up to the radio are black/red and red.

benzedrine · #55 09-19-2010, 07:42 PM

Wow you guys are good! The black connector has a grey/violet wire and a red wire. The red wire could definitely be the constant I was trying to find before. I didn't have time to test it/ try fuses etc. If it is the constant, I'll get to ditch the line to the battery. No sense in having that if its redundant. The radio has no illumination wire on the harness- it lights up the same day or night. Its a real simple (cheap) radio but it will be fine for the time being. Thanks for the info on testing the fuses! You are a huge help.

Thanks a ton for the screw size! I was afraid to experiment and mess up the threads. Now I can put this all back together correctly for the first time in, Im sure, years. The aftermarket radio I took out was about 10 years old. Also thanks for that diagram!

No really thanks, newtodiesel- I appreciate you throwing out suggestions. Without the help from here I wouldn't even know where to begin, so any info is good!!