83 300sd Brake Lights Blown Fuse help please - Page 4 - PeachParts Mercedes-Benz Forum

JamesDean · #46 03-16-2012, 01:48 PM

Quote:

Originally Posted by ShadeTree300SD

On the far right side under the glove box there is only one box on that bracket. Maybe I should get a photo.

Ok, removed the the carpet on the drivers side of the console. There is an odd looking coiled white wire in a deteriorated sheath that goes out the side of the tunnel near the tranny. I saw it while underneath also and it doesn't go to anything. Small gauge white wire, very strange looking.

The cruise control amplifier is located under the driver's side dashboard. Just left of the brake pedal. The warning box is like 2-3 inches to the right of it.

Thats the evaporator drain tube. If its deteriorating, you should consider replacing it. Water flows down through there and if you find a puddle on your floor in the car, you'll know why. I'm not sure why they used that type of hose. Weird stuff.

ShadeTree300SD · #47 03-16-2012, 02:44 PM

Ok, sure enough I had unplugged the stuff under the glove box! So, I unplugged the two units left of the brake pedal. That would be the correct cruise control amplifier and the warning box. Put in another fuse, drove it up to 25-30mph and the fuse blew.

JamesDean · #48 03-16-2012, 03:18 PM

Try that plug at the right of the gas pedal, look at it see if anything looks amiss.

ShadeTree300SD · #49 03-16-2012, 03:18 PM

I think this is the one you just mentioned

Maybe this is something. Under the carpet that is on the drivers side of the console the are two different plug in type connectors 8pin think. One of them closer to the seat and pretty low on the tunnel. The second one is right under the air duct and right up against that wierd evaporator drain hose (very weird stuff). I unplugged this thing and there was this brown gooey substance that had puddle to the low end. It's all around the bottom 2 pins and feels like it's also inside the female side of the connector. Is it possible to removed the female side from it's bracket so I could clean all that out. Since it's tied right to that weird hose I wondering if it has gotten wet??

JamesDean · #50 03-16-2012, 03:22 PM

That might be something indeed! That second one was the one I'm was talking about previously.

If your evaporator drain hose is leaking water into the cabin then it very well could have gotten that connector wet. Disassemble it and clean it up. You might have very well found the problem.

It is possible. I believe you can pry it out with a screw driver, or perhaps move it in one direction or another and it will unclip. I cannot remember.

ShadeTree300SD · #51 03-16-2012, 04:41 PM

Ok, I took the connector closest to the gas pedal apart and cleaned it all up and reassembled it. I popped yet another fuse in the socket and drove off with my fingers crossed! At roughly the same place (speed & distance) I applied the brake and 1 or 2 seconds and pop goes the fuse. I thought, what the cuss!! So, I go back and I decide to unplug the other connection (the one that's about 4-5 inches away towards the rear of the car). I put in yet another fuse and head out. I tried everything and could not get the fuse to blow!! So, is this a victory of some sort? What is this connector for and where do the wires go?? Anyhow, my fingers are still crossed!!

JamesDean · #52 03-16-2012, 04:49 PM

Can you take a picture of this connector, I'm not picturing its location for some reason.

Yak · #53 03-16-2012, 05:18 PM

Quote:

Originally Posted by JamesDean

Can you take a picture of this connector, I'm not picturing its location for some reason.

A pic w/ a brief description of wire colors, since they don't always come through. Quantity of pins, would help too.

ShadeTree300SD · #54 03-16-2012, 05:51 PM

Here's a photo of the connector. The connector with the brown gooey stuff is the one on the left with the purple wires. The one we are talking about now is the one that is unplugged on the right side if the air duct and center of photo.

It is a 8 pin connector wires are as follows:

Top row from left to right - Blank, Red, Red w/white stripe, Brown
Bottom row from left to right - Gray w/purple stripe, Brown, Red w/black stripe, Red w/yellow stripe

ShadeTree300SD · #55 03-16-2012, 08:11 PM

JamesDean, how do you post those great photos? Obviously mine didn't come out very big!

Yak · #56 03-17-2012, 12:15 AM

Is that the connection for the hazard switch? If so, that's between the fuse and the rest of the circuit. It might not be real helpful for tracing it down, since everything downstream could be the cause. E.g. the hazard switch in the console, or the wiring up to the flasher relay behind the cluster, or the combo switch...

Page 2 in the pdf

Do you turn signals work with that unplugged?

JamesDean · #57 03-17-2012, 12:26 AM

I thought that might be for the brake lights. Check them as well.

ShadeTree300SD · #58 03-17-2012, 01:06 PM

So, I took the old girl out for a spin this morning with the same connector unplugged and it would not blow. So I plugged the connector back together and within a couple of brakings from over 25-30 mph it blows. I pull over put in another fuse and unplug the connector. I take it up to 40 and make a hard full stop and the damn thing blows!! So, I'm lost in space again. If I can't replicate without going to speed and braking to a stop, is there a way to use the meter on anything? I've been scratching my head and just can't see a way through. Any thoughts??

Yak · #59 03-17-2012, 02:08 PM

Quote:

Originally Posted by ShadeTree300SD

So, I took the old girl out for a spin this morning with the same connector unplugged and it would not blow. So I plugged the connector back together and within a couple of brakings from over 25-30 mph it blows. I pull over put in another fuse and unplug the connector. I take it up to 40 and make a hard full stop and the damn thing blows!! So, I'm lost in space again. If I can't replicate without going to speed and braking to a stop, is there a way to use the meter on anything? I've been scratching my head and just can't see a way through. Any thoughts??

Okay, matching your description of the connector up, that's C107 and is for the power windows. There's an error in the FSM in the back that ID's this as a 6 pin, it's an 8 pin. You could (if you cared) check pages 130-131 and see that the 7 wires match.

There's no connection between this connector and Fuse 12, so its earlier behavior was a red herring.

Have you disconnected the cruise control switch on the column?

You may also want to remove your instrument cluster and check that out for burned traces.

Can you actually see when it blows via the gauges failing since they're off the same fuse? [Watching your cluster while braking is not a great idea, so you might want an assistant so you can watch the road.]

I would also check brake fluid, and the brake wear sensors. There's a path through to ground via the brake fluid level sensors. If they're low, and the problem occurs under hard braking, maybe it's there. Likewise with path to ground via the wear sensors.

You might also try removing the hazard switch from the console. In theory this should isolate the turn signals from fuse 12. You'd be without signals, but that would mean you drive like other idiots who don't use them.

Another option might be to unplug the warning module (like a relay). This, in theory, should isolate the warning lights, the alternator, and maybe some other things from fuse 12.

Continuing that idea, proceed on to the Top Dead Center amp (?); then maybe the cluster itself. I don't know if you NEED a TDC amp to drive, maybe just for the tach? Maybe not speed, but RPM related? Sheet 4 on the pdf.

ShadeTree300SD · #60 03-17-2012, 04:12 PM

Quote:

Originally Posted by Yak

Okay, matching your description of the connector up, that's C107 and is for the power windows. There's an error in the FSM in the back that ID's this as a 6 pin, it's an 8 pin. You could (if you cared) check pages 130-131 and see that the 7 wires match.

There's no connection between this connector and Fuse 12, so its earlier behavior was a red herring.

It is true that connector was for the power windows. I looked at pages 130-131 and I'm not sure that I fully understand. Is that connection shown? I see everything else and the wire colors are the ones I noted in the connector.