Fused, switched spare 12 volt? - PeachParts Mercedes-Benz Forum

funola · #1 09-20-2008, 07:59 AM

Are there any 12 volt fused spare switched power that I can wire accessories to? If so, are they brought out to the interior or engine compartment?

Diesel911 · #2 09-20-2008, 08:46 PM

Your question is not clear.
Do you want to wire something so that it only works when the Ignition Switch is on and the Engine is running?

funola · #3 09-20-2008, 08:50 PM

yes, coming from the fuse box.

Diesel911 · #4 09-21-2008, 12:09 AM

What is it that you want to hook up?

I do not know of any specific fuse to go to.

If you have a fuse chart (it may still be there under the lid of the fuse box) you can use it to find which fuses go to things that you know only work when the Engine is running.

That will find you a place. But, the problem is that if you hook up something that draws more current than the Fused circuit you pick it will burn that Fuse.
If you hook it up before the Fused Circuit you could burn the Ignition Switch.

You will need to know how many Amps (or Watts) what you plan to hook up will use and that will tell if it is safe or not to use the Fused Circuit.

If it is rated in Watts there is a math formuls to convert it to amps.

Cervan · #5 09-21-2008, 03:48 AM

Fuse 4 inside the w123 fusebox is for acc's. will have positive power in ACC, START and RUN. 8-amp fuse this is what i tapped into for my electro-vacuum shutdown conversion.

funola · #6 09-23-2008, 11:38 AM

Hey, thanks for the info. Here's another electrical question. If all 4 pwr windows don't work, and there are no power to the switches, there are power to the 2 window fuses and the fuses are good, then what is the likely problem? Per the Haynes diagram (very hard to read btw), the is a onnector between the fuses and the window switches. Where is this connector located?

Jeremy5848 · #7 09-23-2008, 01:52 PM

Next, check K4, the power window relay. It lives in the fuse/instrument box under the hood. After taking the fuse cover off, remove six (6) captive screws and take off the box cover. Behind the fuses you will see three columns of relays and such. K4 is the last relay (next to the firewall) in the middle column.

Jeremy

funola · #8 09-23-2008, 05:16 PM

There is one nut after removing the fuse cover, not 6 screws, and there's no relays behind the fuse panel, just a bundle of wires.

Quote:

Originally Posted by Jeremy5848

Next, check K4, the power window relay. It lives in the fuse/instrument box under the hood. After taking the fuse cover off, remove six (6) captive screws and take off the box cover. Behind the fuses you will see three columns of relays and such. K4 is the last relay (next to the firewall) in the middle column.

Jeremy

Diesel911 · #9 09-23-2008, 05:53 PM

What vehicle are you working on? Different model an years may have the relays in different locations,

funola · #10 09-23-2008, 06:08 PM

It's a friend's 83 300TD wagon.

Quote:

Originally Posted by Diesel911

What vehicle are you working on? Different model an years may have the relays in different locations,

Diesel911 · #11 09-24-2008, 12:51 AM

Quote:

Originally Posted by funola

It's a friend's 83 300TD wagon.

I looked up the Window Relay location in the Factory Manual and it tells me behind the insrument cluster. Here is a very muddy pic of the location.

funola · #12 09-24-2008, 05:50 AM

D911, can you tell me from your FSM if the window relay powers the 2 window fuses? Witout a diag I can't do much, with one I can fix anything. I really need to get the electrical portion of the FSM. Is yours on a CD? If so, please recommend source.

Quote:

Originally Posted by Diesel911

I looked up the Window Relay location in the Factory Manual and it tells me behind the insrument cluster. Here is a very muddy pic of the location.

Diesel911 · #13 09-25-2008, 03:18 AM

I could not easily find how to trace the wiring in the CD Manual.
This book has wiring diagrams in it and dose not cost much and is available at local autopart stores.
Haynes 63012 (697)
Mercedes-Benz Diesel 123 Series
1976thru1985 4&5 cyl, 200D,220D, 240TD, 300D, 300CD, 300TD
The info is on pages 291-293 in my book.
They show #27 Relay-I window lifts and #28 Relay-II window lifts.
I am not sure if this means there is 2 styles of relays used or there is more than one relay per vehicle. Also I could not figure out in the short time that I scanned over the wiring diagram how everything was connected to pass that info back to you.
If you can get the car Owner to buy the book for you.
Depending on who you buy the book from the price can be $17-$24. This money might be better spent buying the Factory CD from a Dealer. The one I have covers the same modles as the Haynes manual.
This is a pic of one of my window fuses. It looked good from the front but when I pulled it it was no good.

I wish someone else who knew more about your problem would chime in as I am real weak with electrical stuff.