Low beam weirdness - switch or something else?
 

Guys,

I am struggling to figure out a problem with my low beams that started 6-9 months ago. I've got a couple of ideas on what to do next but I wanted to get some feedback on which way to go.

The car is an '83 SC. Since I bought the car in 2011, I have replaced the H4 headlight bulbs, replaced the turn signal stalk and added the JWest headlight relays. Those mods really improved the headlight brightness. Grounds have all been checked and cleaned.

Back in the spring, I noticed a problem with the low beams. I had been at dinner and when I got out, it was dark. Got in the car to leave, cranked the car and turned on the headlights. They were very, very dim. Got out of the car and did some troubleshooting. Fuses were ok (at least visually). Both brights worked fine.


Anyway, I limped home with just the brights. I thought maybe it was a battery issue so I put the car on the battery minder. The next day the low beams worked fine. Ok. I assumed it was just low battery.

A few months later the same thing happened. This time I verified the battery charge was good with a multimeter. Put it on the battery minder anyway. No change - low beams still don't work. Now the low beams consistently don't work.

My first thought is that the headlight switch in the dash is bad. I've read a lot of threads on the headlight switch failures, but none of them seems to describe this symptom.

My other thought is that maybe I do have a battery problem, but the car cranks fine and everything else with the electrical seems ok. Voltages are normal. The battery is an 8-year-old Optima Red Top. I'm thinking about replacing it with a Yellow Top since I added a stereo amp and it's getting long in the tooth. It's probably a good proactive move before I get stuck somewhere with a dead battery anyway.

Here is a something I noticed that I need someone to help me verify. Prior to installing the headlight relays, I seem to remember that the first stop on the pull knob for the headlights activated the parking lights (no headlights) whether the car was running or not. The second stop activated the parking lights and the headlights were at their normal brightness (again whether or not the car was running). Once the headlight relays were installed, the low beams only came on at their full brightness when the car was running. I think this is because the relays are bypassing the higher current draw from going through the turn signal stalk, so I think that is the expected behavior.

What is happening now is that the first stop on the pull knob activates the parking lights AND the headlights but they are very dim even with the car running. Pulling to the second stop doesn't do anything now -- by that I mean nothing else happens. I don't think this was the normal behavior after installing the headlight relays. Can someone who has the headlight relays installed verify this behavior? If this is different behavior, does this indicate the headlight switch is the likely culprit?

I also tried swapping the headlight relays and no change.

The only things I know to do now are to replace the headlight switch, fuses and battery, but I wanted to see if there something else that I'm maybe missing here. I am at a loss to understand why it's just the low beams that are affected -- and both low beams at that.

Thanks in advance...

I have headllight relays installed and the switch operates the same as it did before I put them in. Either the headlight switch went bad at the same time you added the relays or something may have gotten miswired or disturbed when you did the mod.

Tirwin,

I have an '87 with the JWest headlight relay installed and H4's with city lights. I just checked my behavior.

With no key in the car:
Headlight switch position 1: Parking lights are on and city lights are on (i.e. headlights are on but very dim due to only the 4W bulbs working).

Headlight switch position 2: No change in behavior from position 1.

Key in ignition and turned to position 2:
Headlight switch position 1: Parking lights are on and city lights are on (i.e. headlights are on but very dim due to only the 4W bulbs working). This is the same as with no key in the car.

Headlight switch position 2: Parking lights are on and headlights are on. Presumably the city lights are still on, too.


Do you have city lights on your car? Perhaps what you are experiencing as really dim lights are actually just the city lights without the 55W bulbs ever turning on.

I agree with you that I think prior to installing the relays, the headlights would turn on when you move the headlight switch to position 2 regardless of whether the car is running or not.

There was a long time (at least 18 months) between the installation of the relays and the problem with the low beams not working.

Thanks! That is a huge help.

Is the "city light" you're referring to a separate bulb or integrated into the single bulb? I could be wrong, but I think the H4's just have a single low/high beam bulb. But the behavior you're describing is exactly what I'm seeing.

But working on that idea, it seems like I'm not getting the "full" current to the low beams.

I just looked up the headlight switch and got a little sticker shock. I think I might try replacing one of the headlight relays just to be safe before dropping the money for a new switch. But what are the odds that BOTH relays went bad for the low beams at the same time? If that happened, I should go buy a lottery ticket.

Just a thought... does anyone know of an easy way to bypass the headlight switch? If I could take just it out of the equation and verify that the low beams work, that would tell me for sure that the switch is the culprit, right?

Have you tested the relay for the low beams? They can fail. Swap the feed to the relays from low to high and see if the problem moves with the swap.
Tapping the relay may work as well.

jumper the headlight relay .. that will tell you if the issue is in the priamery circuit ( switch ) or secondary circuit ( headlight)
As you are now running a relay all the headlight switch does is close the relay contact .. once that is done the headlights are lit b

1. battery power ----> relay -----> headlight ------> ground.


so next time it happens just take a fairly heavy ( say 14 guage ) jumper and short the realy contact terminals ( actually you can do it at any time but if it is an intermitent problem it may be hard to tell )

if it now lights up you know the issue is in the relay or the headlight swich ( likely the relay )

if it still is poor lighting see the path above.

Personally I would just swap relays first

The city light is in fact a separate bulb that goes inside of the H4 bucket. It is a 4W bulb, the same as what is used in the front side marker parking lights. They are used in Europe. Check this thread out on them. Specifically, this is what mine look like.

With no key in the ignition, turn the turn signal to left or right. The parking light for that side goes on along with the city light. If you do indeed have city lights and this is the level your headlights are at while the car is running, then the main bulbs are not lighting in the bucket.

You have an Optima Red Top for eight years! And it still works!

Go play the tables....

They can fail but usually it is a problem with them holding enough charge to get the cranking amps....since you start fine the red top is not the prime suspect.

Replace the low beam fuses with new ones. I understand they can look fine but they can be old. I spent a couple of weekends ago 2 hours on figuring out why my left low beam would not come on. I was installing Marchal amplilux with new wiring so figured I done something wrong. 2 hours later I tossed the white fuse out and put in a new one and presto....I can not explain why....but the old one looked fine but old...

Then it is on to the switch unfortunately. But I find that strange since you have put in the relay so it is only being hit with low current....

Are you sure the wiring is still correctly inserted in the 3 prong connectors on the back of your headlamps?

Isolate your issue by activating the relay via a jumper wire to provide direct 12vdc to the relay's pick coil. No need to even pull the headlight switch. The idea is to force the relay to pick (close) and see if headlights are full bright.

I'm betting the relay's internal contacts have burned and now are no loner closing properly.

You could also just try a new relay or move one from another location just for testing.

Also check and clean all fuse contact points and ground points for the head lights.

It's strange that the lights are dim because the power to the lights comes via the relay and not the headlight switch, the switch only activates the relay's pick coil.

I agree, I doubt that the headlight switch is the problem. I bet on a malfuntioning low beam relay or a wiring problem. I would also try to see what happens if the relay outputs are shorted and the light current runs through the short instead of the relay. On my all original "79SC also the bright lights with the headlight switch position-2 only comes on when the engine is running.

Thanks, guys. You've given me some good ideas to check out further. I will do some more troubleshooting and report back.

Not sure what kind of relays you are using but the standard square can relays have these terminals:

85 - one side of pick coil
86 - other side of pick coil
30 - input feed
87 - normally open
87a - normally closed

Without 12 vdc across the pick coil you have 30 connected to 87a (normally closed position)
Then is you apply 12vdc across 85 and 86 it powers the pick coil and the relay activates to the other position and connects 30 to 87 while disconnecting 30 to 87a.

This is a Single Pole Double Throw style relay. Usually you have battery voltage on #30 and the headlight on #87. Then 87a is not used.
Finally 85 goes to ground and 86 goes to the headlight switch. When 86 gets power then the coil picks and contacts close 30 and 87 so power flows from 30 to 87.

This may help, it's a very nicely done relay setup for hi and lo beams as well as driving lights. Everything on relays. Driving lights come on with hi-beams or they can be commanded on independently. You decide what you like by placing the purple jumper.

http://forums.pelicanparts.com/uploa...1383869224.jpg

A'ight. I'm in. Tippy if I'm buttin' in tell me to but out. I'll start another thread, but I'll be damned if I don't have almost the same thing happening with my '86 I just hadn't figured it all out until I read your posted and tested it out just now.

The change in my headlamp behavior was coincidental to dropping in a new alternator about a month ago. Emphasis on coincidental b/c I can't wrap my head around why a new alternator would make a difference.

'86 that came to me with H4s and relays. One relay for high and one for low beams. Optima red top less than one year old.

Before new alt. and for the last 16 months my headlamps behaved as described by wrxnofx and what I understood as normal. Key off, light switch to position one turns on the running lights and city lights. Light switch to position two and no change. No headlamps. Turn key on. Light switch to position one turns on runnning/city lights. Light switch to position two turns on the main headlamp bulbs. Low beams/high beams depending on position of stalk.

Currently with key off. Light switch to position one turns on running/city lights. Position two turns on main headlamps bulbs. Until today I thought the main headlamp bulbs were coming on full bright but your post changed that.

So key off, light switch to position two and headlamps are on. Bright enough to make me think they are full on until I thumb the key over to run and the headlamps jump to full brightness. It's clear to me now I'm getting the same "dim" light you are describing until the key is on.

I'm also blowing fog lamp fuses. Started same time. First time I tested and found my fog lamp relay bad. Replaced that along with fuse and I was good for a week of so, then blew the fuse again.

Looks like I'll be cleaning a bit of a rat's nest along with testing and likely replacing the relays this weekend. If I get anywhere I'll post progress.

Anyone have any comments on two vs. four relays for the H4 headlamps? -J

2 relays have been working fine for my H4's for the past 2 years.

JAR,

Pile on brother! Hopefully we'll all get it sorted out.

I am hoping to get back to my troubleshooting this weekend. If football doesn't get in the way! :)

Would topic 13 of this thread help at all? Sorry to not be of more help.

SIDENOTE: Best avatar ever, topic 14.

Short terminals 30 to 87 and the thing should light .. good catch with the fuse connections. They are carrying all the current.

OK. I think I have mine pinned down to the light switch. Read about 50 threads, studied the Bentley 'til my head hurt. Huge kudos to Canada Kev for the work in this thread. His chart made this much easier.

http://forums.pelicanparts.com/porsche-911-technical-forum/475738-headlights-not-working-properly.html

My relays. Lord bless the PO. I hadn't ever paid too much attention to these other than to say, "Cool, it's already got relays." Not a kit but a pair of Bosch relays. 16g wiring on the power side so that's not great. Here's the part that doesn't make any sense though. To power the relays (30) instead of taking power off the battery with a fused wire the PO took power from the top of the fuse panel at the ganged terminal 7/8/9 (counting from the back). These three are powered by red/yellow from where? The ignition switch. So to my reasoning (feel free to correct me) PO avoided running headlamp current through the light switch and instead sent it through the ignition switch. I'll be correcting this. Manually jumpering the relays work fine.

On to the switch. After I realized the relays weren't the cause I backed up and found the above linked thread. Both ends to the middle may not be the best plan but checking the light switch seemed easier that chasing the wiring harness for shorts.

On the back of the light switch using Canada Kev's guide.

(30) Red is constant hot 12v. Checked out good.

(65) White/black feeds the headlamps via the turn signal stalk. This should be hot only with key on and light switch all the way out to position 2. I'm getting 9v to (65) with key off and switch in pos. 2. Shouldn't be happening. Here's my not quite full brightness headlamps.

(75) Red/white from ignition. Red/white to the turn signal stalk. Should be hot only with key in Run. With the key off and out I show 9v with the light switch full out in position 2. I disconnected both red/white wires from (75) at the light switch. With switch in full out I'm showing 9v. There shouldn't be voltage without any feed from the ignition switch.

Current plan is to order a new light switch. To my reasoning the light switch is allowing power where it shouldn't be. Electricity and wiring might as well be VooDoo to me so any and all comments are welcome. I'm going to drink a beer and celebrate Ole Miss beating Arkansas and get ready for LSU vs Bama. Hopefully the Tigers bring their A game. -J