Headlight Issue

[TodB]

My headlights and electric windows stopped working (they did work a week ago) though parking lights, all turn indicators and other lights work. Flashing the high beams via the left stalk also works which tells me that the fuses and wiring to the headlights are OK

I am thinking it must be in the headlight switch or another relay though the parking lights work when I pull the headlight switch out half way

I did read about a another headlight relay next to the fuse box which looks like a bitch to get to. It looks like its the same relay type as is used in the engine compartment. I may try to swap that next if I can find one today. Can someone confirm which of the three relays is actually the headlight relay?

Any other thoughts or suggestions? Not sure what the relation is to the all of the windows not working...

 

[Mario L.]

twist all fuses to make certain they have good connections . . these old style fuses will get minor corrosion that is enough to stop the flow of electrons . . .

Mario L.

 

[HB Chris]

And unless you have a `74 there is no low beam relay. You might have some issues with the load protection relay which is under the dash, it affects windows and other systems.

 

[TodB]

headlights

You might have some issues with the load protection relay which is under the dash, it affects windows and other systems.

Which of the three relays is it?I cannot find anything to tell me what relay is what. Regardless, all of those relays are not made anymore to my knowledge. What's the replacement part #?

 

[HB Chris]

I unfortunately don't know which is the load shed relay. On a US `73 it will click when you open the driver's door, it is connected to the interior light switch ground. The window switches work when the engine is on but stop when the ignition is off. Opening the door allows the switch to work again, this was to prevent someone from trying to actuate the window switches from outside of a locked car I presume. Earlier cars are different. You can test a relay by removing it and providing power to terminal 85 and a ground to 86 (I think).

 

[jmackro]

Which of the three relays is it?I cannot find anything to tell me what relay is what. Regardless, all of those relays are not made anymore to my knowledge. What's the replacement part #?

What year is your coupe? On my 1970 2800 the load shedding relay (kind of a misleading name) is the one closest to the firewall, above the hood release lever. It is rectangular in shape, and has 4 terminals.

You are right, they are NLS. You may be able to fix yours (assuming it is bad) by cleaning the contacts. The cover comes off fairly easily. If the coil isn't working - that is, it doesn't click when you turn on the key - then you need to find a good used relay.

 

[TodB]

headlights

Thanks for your reply, Jay.

I, too, have a 1970 2800Cs so I will start by removing and testing the relay to see if it works. I am hoping that its the culprit.

If it does not, is there harm in replacing it with a "modern" similarly pinned one?

 

[jmackro]

I, too, have a 1970 2800Cs so I will start by removing and testing the relay to see if it works. I am hoping that its the culprit.

If it does not, is there harm in replacing it with a "modern" similarly pinned one?

Well two issues with a non-stock replacement:

- The pin configuration is unique - not the same pattern as a horn or headlight relay.

- The load shedding relay handles a LOT of current - pretty much everything electrical on the car goes through it. You would need a fairly beefy relay as a substitute, or several horn relays in parallel.

A simple way to locate and partially test the LS relay is to put your hand on it while operating the ignition switch with the other hand - if the coil is working and the relay "clicks" you will feel it. Of course, if the points are fried, it might click without making contact.

 

[TodB]

Headlights

A simple way to locate and partially test the LS relay is to put your hand on it while operating the ignition switch with the other hand - if the coil is working and the relay "clicks" you will feel it.

I tried this and I can feel and hear the click from the relay.

When I pull the headlight switch out halfway, the rear parking lights go on but not the fronts. Is there a way to test or bypass the headlight switch to eliminate it as a suspect?

 

[JhwShark]

Tod,
I only have a '72cs wiring diagram with parking and turn lights in a dual filament bulb: two leads + one ground lead.

Parking lamps Left is gry-yel and right is gry-wht...left is fuse 1 right is fuse 3...they both go to the light switch as left gry-blk and right as gry-grn.

From experience the lights on German cars are usually on left and right circuits not front and back...as the digram indicates...but that does not run on serial wires such that the front wire could be off of both 1 & 3 fuse...two wires off of each fuse to the lights and one wire from other side of fuse to switch...low odds for both to be off, but check...so I am at a loss for helping further.

I do note that front left gry-yel goes to the engine compartment light which is grounded after the compartment switch...maybe if this light is bad or the switch is this could cause front to not function.

Post a wiring diagram of your model year if you have one. I have a '72 euro csi and only have single filament turn lamps without the parking...on my '72 2002 euro, which had similar configuration, I added/modified the turnlights to have parking light function...I may do this to my e9.
Jon

adding...You could pull the wires (ref'd above) off of the switch and touch with 12v to see if the lights illuminate.

 

[TodB]

headlights

parking lights...they both go to the light switch as left gry-blk and right as gry-grn.

Pulled the headlight switch.

No surprise, putting 12v to the rear parking lights lines works (did begfore). Did not work for headlights though I was not sure which wires to apply power to. In lieu of no wiring diagram I tried them all:-D

to the engine compartment light which is grounded after the compartment switch...maybe if this light is bad or the switch is this could cause front to not function.

I have not had an engine compartment light for years as it hits my air filter housing.

The only other variable is that I had an alignment completed a week or so ago. Is there a ground wire that could have been jarred or loosened? Seems remote...

 

[JhwShark]

A loose ground wire could be a cause (an Open circuit). Ground for the turn light is inside the light assembly.

Do your turn signals work up front?? if so, then not a ground.

Also, confirm if US or Euro...dual filament turn/parking light or turn light on fender and parking light within the lowbeam...

Please give input to colour of:
lft frnt turn light lead and left front parking lead and the associated ground colour
same for the right

I am surprised you have a front and back circuit not left right.
...but I may be mixing make and models of my german cars...

 

[TodB]

Headlights

Do your turn signals work up front?? if so, then not a ground.

Yes, all lights work except the front parking and headlights. Flashing the headlights via the left stock works as well.

Also, confirm if US or Euro...dual filament turn/parking light or turn light on fender and parking light within the lowbeam...

1970 US 2800cs with dedicated parking lights (combined with turn signals)

Please give input to colour of:
lft frnt turn light lead and left front parking lead and the associated ground colour same for the right

Left - two hot wires, one gray with yellow tracer, one green with red tracer

I am surprised you have a front and back circuit not left right.

I don't think I do. The fuse box is labeled left and right
I appreciate the help!

 

[HB Chris]

If headlights don't work it could be the hi-lo stalk on the left, power goes through that to the hi and low beams and the headlights have no fuses, it is an unprotected circuit. Yellow is low beam, white is high beam.

 

[JhwShark]

I'll try some more...knowing the lowbeams don't work let's target dimmer switch...yellow lead takes 12v to low beam it comes from dimmer switch and yell-white gets power from light switch. White wire from dimmer hits the Highbeam relay.

I'm assuming other electronics are ok: hazards, wipers, horn, fans...

You'll need your volt meter.
So, is there 12v at the yellow wire at the dimmer switch when the light switch is on; and the yell-white? Is the lowbeam brown ground lead connected, both sides?

 

[TodB]

headlights

If headlights don't work it could be the hi-lo stalk on the left, power goes through that to the hi and low beams and the headlights have no fuses, it is an unprotected circuit.

OK, I am narrowing in on it. Everything works normally except the radio, headlights and fan. Shifting the high beam stock up and pulling back on it powers the headlights and then the fan and radio come on (some fine wiring design!). Tomorrow I'll pull the lower steering column cover off and see what is going on in there.Thanks for the tips.

 

[JhwShark]

This is an interesting one...you should also have a green wire at the dimmer switch this goes to and shares fuse 6 with greens to light switch and load sharing relay. Fuse 9 is for the fan/blower and window motors grn-brn wire and fuse 10 is for the Radio a violet wire.

I'm looking forward to what you find under there, take a few pics include the fuse block...

 

[TodB]

Now that I think about it...

I did have one instance last year when the headlights worked but switched off when I turned on the hi beams via the stalk which was a bit unnerving when bombing down the highway at night. And then the issue just went away.

I just took the lower panel off of the steering column but I need to pull the wheel to see the entire hi beam switch.

More to follow tomorrow.

 

[TodB]

Update

The switch seems to be in working order but pulling back slightly on the high beam stalk causes the headlights, radio and fan to work. The switch really does not come apart easily so if anyone has a used one from a donor car, please let me know. they come out pretty easily.

Today, my E28 left me in a no start condition at lunch (arrggh), Came home, got the coupe and went back to work. On the way home, I went over a bump and voila, the fan and radio kicked on and the lights now work.

I then went back to the E28 which, of course, started right up.

I love old cars.:-D

 

[merdad]

My #4 fuse that feeds the headlight switch was getting hot. So, I decided to put a seperate relay for the low beams, I pulled the two yellow wires off the connectors under the fuse box, On a single yellow wire coming from the headlights, I put an inline 20A fuse and fed it to the relay, and also fed the two yellow wires that went to the switch and the H/L beam stalk to the ralay, brought a hot wire from the connectors under the fuse that came direct from the battery to the relay and grounded the relay. Now I have the low beams on relay too and all is normal.
My relay is under the dash for the moment, but will eventually move it to the empty spot next to hight beam and horn relay by the battery.
My car is a 72 Euro.