High-Beam Problem

[Dadstoy]

I installed a pair of driving lights in place of the stock fog lights last Christmas. I used the stock fog-light relay and moved one wire behind to make them come on with the high beams instead of the lows.

Shortly after that, the high beams started acting strange. Sometimes they wouldn't come on, sometimes only one would come on, and sometimes they would come on but the driving lights would not.

Now the problem seems to have settled into just one symptom. The driving lights come on instead of the high beams. The high beams come on when I pull the stalk toward me, but they go dark when I switch it away.

I looked for a problem with the driving light's relay but couldn't find one. I also didn't see a relay for the headlights.

Any ideas on what the problem might be?

[scottb]

Originally Posted by Dadstoy

I . . . moved one wire behind to make them come on with the high beams instead of the lows.

If I understand correctly, now the high beams and driving lights are all controlled through the stalk switch. That's an awful lot of amperage running through that switch. The switch is notorious for going bad with just the high beams running through it. Now you've added more amperage going through it.

My guess is that the switch is "fried." You should replace the switch. At the same time, install the Sucro headlight relay kit. Replacing the switch and installing the relay kit are not difficult.

Good luck!

[jonbot]

Dadstoy, do the driving lights come on when you pull the stalk toward you? Or just the high beams?

[Dadstoy]

Originally Posted by jonbot

Dadstoy, do the driving lights come on when you pull the stalk toward you? Or just the high beams?

Just the high beams when you pull the stock toward you.

I don't think any extra current is running through the stalk because the relay clicks when the driving lights come on, and if I remove the relay, they no longer come on.

[jonbot]

It's hard to confirm 100% from here, but from what you've said, I'd agree with scottb's diagnosis that the culprit is the High Beam contacts in the turning stalk. I think the design is less than desirable, but on the other hand, it has lasted 23 years.

The best way to check it would be to put an ohm meter across the "high-beam contacts" and see if you get 0 ohms when you push the stalk away from you. However you fix the problem, the relay kit will be a good plan.

Good luck with it!



Jon

[Dadstoy]

I will check that out, thanks. What will I accomplish by upgrading to the relay kit if the driving lights are already controlled by the fog-light relay?

[jonbot]

Originally Posted by Dadstoy

I will check that out, thanks. What will I accomplish by upgrading to the relay kit if the driving lights are already controlled by the fog-light relay?

Good question, the upgrade will divert the high current draw of the headlamps away from the turning stalk, and instead the load will be placed on the relays. There are several benefits to this, one of them is that relays are much cheaper and easier to replace than turning stalks.

Jon

[Dadstoy]

Ah. That makes sense. Every other car I've worked on was already set up that way. It sort of surprised me when I found out that the 911 was not.

[jonbot]

Originally Posted by Dadstoy

Ah. That makes sense. Every other car I've worked on was already set up that way. It sort of surprised me when I found out that the 911 was not.

Me too, especially when the fog lights have their own relay I guess this goes with the whole theory that cars are designed to be on the road for x years, so the fact that it was still running up until now says a great deal for the original design.

I thought I'd add another benefit to the kit,

The way the system came from Porsche, the current to the headlights has to travel a long path up from the battery, through the headlight switch, to the turning stalk, through the turning stalk's ~20 year old contacts, back down to the fusebox, through the fusebox's ~20 year old contacts, through various ~20 year old connectors and plugs, and then finally to the headlights.

The relay kit (from what I understand) changes the path so instead it travels from the battery, through the relay's contacts, to the fuses, then to the lights. This path is shorter, and while it still has to travel through a small amount of ~20 year old contacts, the overall length of wire traveled is shorter, and the overall resistance is less, meaning less heat is generated, and meaning more energy is conserved and less is wasted. This increases the efficiency of the system, and I wouldn't be surprised if your lights also burned brighter after the upgrade.

I just ordered one of these kits myself, as my turning stalk "went out" and I don't want the same thing to happen to the replacement.