W123 300D wiring loom advice - PeachParts Mercedes-Benz Forum

Stretch · #1 10-15-2011, 10:49 AM

G'day All,

I've just thought of a good winter project whilst my car is stripped down and naked.

I'm going to make up my own wiring loom.

I plan to use the existing colour codes so when I come to fit it it will be as standard as possible. However, I will be adding some updates to the car:-

1) An electric cooling fan
2) A tachometer
3) Loudspeaker wires not wired through the fader switch
4) And whilst I'll not be adding a tow bar I think that now is the time to add in the wiring just in case

Can any one think anything else that would or could be useful in the future?

(Power in the boot / trunk?)

What would you add to your wiring loom if you had the opportunity?

What electrical attachments have you added to your car(s) in the past?(!)

I'm starting with a bog standard 123.130 wiring loom so I'll be basing everything on that.

Lastly any tips from the auto electricians out there?

Best wire?
Best insulation?
Best connectors?

toomany MBZ · #2 10-15-2011, 02:27 PM

I would think a 12v power outlet or two on the dash for a cell phone charger, gps or the like.

Not sure what something in the trunk would be for, but it can't hurt.

sixto · #3 10-15-2011, 02:39 PM

CAN bus

Electric antenna? C-pillar reading lights? W126 roller blind? W126 highway horn? Electric mirrors? Heated mirrors (must be standard where you are)? Do T123s have rear door speakers?

Sixto
87 300D

layback40 · #4 10-15-2011, 07:18 PM

Relay/upgrade wires to headlights.
Under hood trouble light.
Back seat power outlets. Kids DVD/ Laptop supply.
Cruse control.
High up stop light. (Rear window location).
Power outlet adjacent to cup holder for immersion heater. (coffee warmer)
Upgrade alt to battery wire.
Upgrade GP's.
Reversing camera.
Vanity light around mirror in sun visors (like W124)
Passenger ejector seat (now I am being silly)

vstech · #5 10-15-2011, 09:08 PM

Hmmm. High voltage theft deterrant?

I installed an internal fuse box in my 79TD, I also ran a #4 pair of cables off the terminal strip to feed an inverter for 1500Watts of 110V power.
after the upgrade to a 140amp alternator (which went with the car when I traded it...) I also installed 3 12v power sockets, one above the hood release lever, one under the ignition switch, and one under the glove box.
I never went beyond the dashboard, but considered outlets, in the two fenderwells for toys back there... in a sedan, I suppose outlets on either side of the center tunnel would be helpful for trips and toys...
if you are rewiring the sound, you might as well run a power feed for a sub/amp to the trunk... along with a retractable service light to replace the cargo light.

Stretch · #6 10-16-2011, 03:46 AM

Great ideas folks - I especially like the ejector seat idea!

Yak · #7 10-16-2011, 02:23 PM

An ammeter or voltmeter? Is there a VDO or similar OE-looking product that can be integrated into the cluster?

Maybe the 126 external temperature sensor built into the existing spot for the W123 cluster? I know there are a few folks who try to pull these off the JY cars here, so maybe they could provide a kit via mail.

Different battery terminals w/ a disconnect? Moroso Performance 74103 Battery Cable Disconnect Switch - Car/Truck/S

Are there any good under-hood trouble or work lights? A flashlight (torch, based on the OP's location) would probably be better, but maybe something for when the batteries run out.

Zacharias · #8 10-16-2011, 03:27 PM

Quote:

Originally Posted by Yak

Are there any good under-hood trouble or work lights? A flashlight (torch, based on the OP's location) would probably be better, but maybe something for when the batteries run out.

I carry a 12v trouble light in the trunk but it never occurred to me that it could be permanently wired in under the hood. What a concept....

layback40 · #9 10-16-2011, 08:49 PM

Quote:

Originally Posted by Zacharias

I carry a 12v trouble light in the trunk but it never occurred to me that it could be permanently wired in under the hood. What a concept....

Some British cars had them the 1950's, even with built in switches so they came on when you lifted the hood. My jeep (Daimler-Chrysler) has one.

I used to use a 55w spot light as a trouble light, thing was, if the problem wasnt a flat battery, chances are it would be by the time you fixed the original problem.

A LED type of light would be good as they use very little power.

GLIDEHM · #10 10-16-2011, 10:38 PM

Thought this bit of info might help some people with a retractable underhood light. Mid 90s chevrolet trucks had a wind up under hood light already installed. It had about a ten foot cord on an enclosed reel that simply winds up by hand when you are done with it. They made it this way so that you could use the light when changing a tire a night, even at the rear of the truck. Simple 12v light already put together for anyone that might want to source one from the pull-a-part. Hope this helps someone!

Stretch · #11 10-17-2011, 05:29 AM

Hmmm LED lights - low power sucking LED lights... nice idea.

I've already bought some H4 low energy twice as bright as the originals from Philips. (Sorry layback they are European spec - not the portable sun Australian scare the living crap out of the wild life versions that will shine from Melbourne to Tasmania. So there's no point you getting excited!)

I also want to make provisions for my planned measure everything data acquisition system - I want to wire up sensors to measure temperature, pressure, flow... but I think I'm going to make that a separate easy to remove system...

Stretch · #12 10-24-2011, 10:26 AM

I've found this thread from whunter about wire types

Automotive WIRE, what you should know

Looks like I'll be costing up SXL high temp stuff

SXL Automotive Primary Wire - Buy online from Allied Wire and Cable | Distributor of Automotive Primary Wire & Battery Cable

Stretch · #13 10-24-2011, 01:44 PM

Excellent resource here

Wiring Your Car - Part 1