I read an article about 2 years ago on the benefits of daytime running lights. The NTSB gave them high marks for assisting drives to see a vehicle more easily. Anyway, I bought a 1983 300SD and I thought about trying to hook up the fog lamps as daytime running lights. I know, purists are cringing about now. So here is how you do it if you are interested.

The process started with the fuse box, which is under the hood on my model. I looked at the inside cover of the fuse box and saw that fuse #14 was a 25 amp, it was for the rear defroster and heated seats (which I don’t have) so it had amperage to spare. I tested the fuse with a voltmeter and found it was hot only when the ignition was fully on and was cold when the ignition was off, perfect. There are two recessed screws toward the front of the fuse rack, remove them and gently pull the fuse rack up. You can then locate the screw connection for fuse #14. I took some 12 gauge wire, crimped a connector to the end and removed the connection screw to #14 fuse and put the wire on it and screwed it down. I then ran the wire through the side of the box (snip one of the rubber grommet and put the wire through). I ran it through the firewall (again through a grommet) and brought the wire into the engine compartment proper. I put a toggle switch on a bracket near the firewall that wasn’t used for anything. I ran the wire to it and connected to one side.

Now, at the headlight assemblies there is a 4-prong plug that is the connection for the fog and headlights. After much testing I found that pin #1 was the hot for the fog lamp. I decided to hook up the drivers side first. I put a splice box on the wire and connected that to the toggle switch I had installed. With my fingers crossed I tested the “running lights”. To my surprise BOTH fog light came on! I tested everything with a voltmeter to make sure I had not created a voltage back flow or short. I also tested all my electric apparatuses in the car to make sure they worked. I even turned on the fog light with the switch inside the car (albeit they were already on) and all was fine. I check all the fuses in the fuse box and all were fine. I made sure that the wires were not over heating also. Everything was just fine.

So, I have been driving for a week and have not had any problems with the set up. The running lights give the car a newer look when it’s going down the road. I did it for safety reasons and I am glad I did. It makes me feel better when my wife and kids have that little bit of extra protection.

And for all the purist out there, all I have to do to return it to stock is flip the toggle switch under the hood and the whole set up is neutralized.

All of this is for what it’s worth………….

__________________
Clancy Priest
1983 300SD Turbo
190k miles
My first MB!

I am geting the euro lights in soon.
They have sockets for parking lights (right under the head light bulbs). I wonder if I can use them for driving lights instead, using the same precedure ?!

DMITRY, the only advice I can give you is test, test, test with a voltmeter to make sure you don't create a voltage backflow or a short somewhere.

Good luck....

I thought in this case I can't srew anything up, since it will be a straight whire from power source. No switches involved. Thise lights are ususaly left unused anyway.

Ya know, you are right. I did not see that. If you wire them direct with no other connection tou should be fine. Just make sure you use a fuse that has enough amps to handle the lights and is only hot when the ignition is full on.

I use fog lamps on my 91 350SDL as DRL'S simply by selecting parking light position on the light switch and pulling the knob outward - turns on parking and fog lights only.

Clancy
 

What a gluton from punishment you are. There are marketed units that turn any light you want when the engine starts with 75% brightness and have a timed delay OFF. Or use your Fog lights by simply turning them ON. I use the type I referred to on my fog lights. Cheap, solid state device, reliable and effective. You really went a long way to get something that was right in your hand, or in a J.C.Whitney Catalog #646J-01, page 103, item # 13AS5227R, cost $24.99.
As to the effectivness of DRL in the prevention of head on collisons, this was studied when the highways were two lane not divided. The National Safety something did the study in the mid 1950s. After market manufacturers jumped to it and there were all sorts of lights on the market. Someone similiar to Ralph N. came up with the bright idea that the automobile had two of the best DRL available, the Headlights, turn them ON. Happy Trails Beep Beep from Houston.

Donald
running lit-up@0.75 of 80watts.

[Edited by Donald L. Swinford on 01-24-2001 at 11:15 PM]

I only see one problem with turning the headlights on during the day without some sort of ignition control or timer...

If you are like me, during the day you would forget the lights were on when parking and voila. Dead battery if you don't get back soon enough.

Now of course there is the buzzer if you leave the lights on on some cars.

Alon

Ashman
 

You were taught as a very young driving student that before you turned the engine OFF, you turned OFF all of the other things FIRST. Roll up the windows, remove the key from the ignition, push the locking knob down, hold the outside handle and close the door. Boy those were the good old days.

Happy Trails Beep Beep from lites ON houston.
Donald

heheeh you obviously havent been to the DMV to get a license as a 16 year old in 1991 my driving test took all of 10 minutes to do.

Drive down the block, parallel park, do a 3 point turn, make a right turn on a corner, turn left at an intersection, and pull back into the DMV. easy as cake, and a 98 on the test, a 95 on the written.

Donald in actuality all I am really saying is people get careless and some will end up leaving the lights on.

Me, I always turn everything off before I turn off the car. Radio, AC/Heater, Close sunroof, windows, etc. Lights off if they are on. Then I turn off the car. get out and lock it. It must be a habit. I lock it even if just running into a store for 1 minute sometimes.

I sometimes even lock it by accident when filling up with gas. Sometimes I even lock it and unlock it then relock it to make sure its locked. hehe. I guess I'm just weird like that.

But I tend to find that many people around, bluntly put, are idiots, and will end up doing something stupid liek leaving the lights on etc.

Better to be safe than sorry I say, can't go wrong if they turn off when the car turns off.

Ever notice how BMW's turn off the headlights but leave the parking lights on if the ignition is off and the switch is left on.

I guess BMW just figures Everyone is capable of being stupid and leaving the lights on. at least the parking lights wont drain the battery as quick. hehe

I myself just have no need for DRL's. Only time I think headlights need to be on is when you can't see.

Alon

Ashman
 

Well said, you can't overdo anything that is good. As for me, my turn everything OFF and last the MASTER came from my flying years. You should get the habit of driving with either the headlamps or the fogs on, it's life insurance.

Happy Trails Beep Beep from
lit up Houston.

Wrong Lights, Right Idea?
 

What I hate is people driving around with their PARKING lights on! Drives me nuts! Donald knows what I mean. Headlamps for driving, parking lamps for parking, right, Mr. Swinford? These damn kids nowadays, no respect, I tell ya!

But, on the issue of lights and traffic safety, whatever happened to the "flashing" headlamps on motorcycles that were supposed to be safe? Didn't last long...

Clancy, yer a crazy nut! Everytime I drive with my foglamps on for safety (like in the serious rain we had today), some Jerk o' napes hasta give the the brights to tell me what I already knew, and he wasn't bright (pardon the pun) enough to figure out, They Are Fog Lamps, You IDIOT!

You want safety? Put a gigundous diesel truck airhorn in your Mercedes, and don't be afraid to use it either! Bleet, Bleet? What the hell did Mercedes have in mind there? Sounds like a stinkin' VW, I tell ya!

Longston
 

You're right. I remember taking delivery of my '87 W124030 and the salesman checking me out in my new dream machine and he depressed the horn on. $42,590.00 and I get a VW horn! I have two of them, the alarm system sounds the same! I was flipped out. Today I still have the road runner sound, I tell people it came from a Dodge Super Road Runner. I keep it as a novelty. Now I have been found out, Beep Beep. Happy Trails Beep Beep from Houston.

Donald

ATTABOY, Clancy!! Congrats on the fogs as DRL'S!
As for me, no prob. remembering the switches. Like Don said - after stopping, brakes "ON", all aux. switches "OFF"; then master switch "OFF" - this possibly also from flying experience (B-52's & "puddle jumpers").

BTW, I've always thought the MB "BEEP BEEP" horn sounds a light ridciculous, too.

Wilton - no kid at 67, including 53 years of safe driving and flying - even on the ground and above all of CA.

Wilton
 

UP UP and AWAY. Yep DRL/FOG LITES. I have the auto on system for DRL. My fogs are 80 watt and the DRL unit turns them on at 75% of in put voltage. I use the EMF of the coil wire to induce a current flow that becomes the on switch. They turn on when there is current flowing through the coil wire, even as your are cranking the engine to start. It also gives me delay OFF, not much but it was free. It is a simple and cheap unit from J.C.Whitney. Read my remarks to Clancy for the part info.
Happy Trails Beep Beep from foggy Houston
Donald, always in a fog