[freebird69]

The head lights and dash lights on my 69 Firebird are noticeably dim and my horn is not very loud. I am not electrical savvy so I asked a couple of my classic car buddies and they said it's a symptom of old wiring.

Is this true? Does wiring degrade over time and then not transfer proper voltage or whatever? These same guys converted their lights to LED but I am curious to know what the actual underlying issue is.

[Stuart]

It seems that 90% of the time, electrical issues in cars are due to poor connections (particularly ground connections.) First thing I'd do is methodically go through the wiring to clean and tighten any wire terminals or ground screws.

[freebird69]

Originally Posted by Stuart

It seems that 90% of the time, electrical issues in cars are due to poor connections (particularly ground connections.) First thing I'd do is methodically go through the wiring to clean and tighten any wire terminals or ground screws.

That's a good tip and I will do that but it still puzzles me that so many things seem to be affected as if many grounds and terminals have issues.

Thanks, Stuart.

["QUICK-SILVER"]

Some brands are worse than others, but sealed beam and halogen headlights get dim with age. Even when they're not used.

I'd start by getting the charging system checked out. Could be low output from the alternator caused by something as simple as belt slip.

Clay

[freebird69]

Originally Posted by "QUICK-SILVER"

Some brands are worse than others, but sealed beam and halogen headlights get dim with age. Even when they're not used.

I'd start by getting the charging system checked out. Could be low output from the alternator caused by something as simple as belt slip.

Clay

Thanks Clay, but wouldn't my alt meter gauge show the low output? FYI, the issue I'm having has been going on for years. I had a headlight go out a few years ago so I replaced both with halogens but they are still dimmer than they should be.

[JLMounce]

Very old wiring can oxidize enough to start causing conductivity issues, but the wire sheathing would have to be pretty nonexistent for that to realistically happen. What does happen with old wiring is loose and corroded connections, including grounding etc. It's also typical to see decades of poor wiring added/subtracted from these cars which can have an effect on conductivity as well.

As mentioned already, I'd start by hitting all of the grounds. There will be several in the engine bay for components like the horns, voltage regulator, battery to engine block as well as the engine to chassis grounds. In the interior of the car most of the grounding is handled on the dash carrier through a series of steel sheets that are laid into and across components in the dash carrier. There will be a triangle shaped piece that grounds the light and dimmer switch. There is also a strap that runs from the dash bezel down to the cigarette lighter and across the face of the HVAC controls and radio that then attaches to the lower right most bolt holding the dash carrier in place.

There are grounds for the sending unit/tank and rear light harness at the back of the car that should be attached near the trunk latch support.

Make sure all of these are secure and free of corrosion. Of special interest in your case will be the horn grounds up front on/near the core support and the dash carrier grounds.

While you're in and under the car checking these grounds, look for overly brittle or broken wiring, connections that are loose and specifically look for modified wiring using butt connectors etc. If you find that the wiring looks to be in terrible shape over-all and has maybe been hacked apart and put back together through the years, it will typically be worth your while to put new wiring in the car. You need to remove the dash carrier to really inspect the grounding there. That's a really great time to replace a dash harness. The engine and forward light harness is a Saturday afternoon job with a couple beers.

On the horns specifically, they themselves will degrade over time as lubrication dries up or they inject dust from over the years. It may not be an electrical issue as a result, but might be that the horns need rebuilt.

[freebird69]

Originally Posted by JLMounce

Very old wiring can oxidize enough to start causing conductivity issues, but the wire sheathing would have to be pretty nonexistent for that to realistically happen. What does happen with old wiring is loose and corroded connections, including grounding etc. It's also typical to see decades of poor wiring added/subtracted from these cars which can have an effect on conductivity as well.

As mentioned already, I'd start by hitting all of the grounds. There will be several in the engine bay for components like the horns, voltage regulator, battery to engine block as well as the engine to chassis grounds. In the interior of the car most of the grounding is handled on the dash carrier through a series of steel sheets that are laid into and across components in the dash carrier. There will be a triangle shaped piece that grounds the light and dimmer switch. There is also a strap that runs from the dash bezel down to the cigarette lighter and across the face of the HVAC controls and radio that then attaches to the lower right most bolt holding the dash carrier in place.

There are grounds for the sending unit/tank and rear light harness at the back of the car that should be attached near the trunk latch support.

Make sure all of these are secure and free of corrosion. Of special interest in your case will be the horn grounds up front on/near the core support and the dash carrier grounds.

While you're in and under the car checking these grounds, look for overly brittle or broken wiring, connections that are loose and specifically look for modified wiring using butt connectors etc. If you find that the wiring looks to be in terrible shape over-all and has maybe been hacked apart and put back together through the years, it will typically be worth your while to put new wiring in the car. You need to remove the dash carrier to really inspect the grounding there. That's a really great time to replace a dash harness. The engine and forward light harness is a saturday afternoon job with a couple beers.

Thanks for that detailed response Jason. I would love to just replace my wiring but my electrical skills a weak. I may take a shot at it though if checking the grounds, etc doesn't work.

What about relays? Could they be suspect?

[Goatracer1]

When you added the Halogen lights did you add a headlight relay? They require more amperage so it's a good idea. I've added relays for the headlights on all my old cars even with regular bulbs since it eliminates all the old wiring and the switch from handling all that amperage.

[Bill Hanlon]

Both the headlights and dash lights use power supplied to the headlight switch. I'd start by looking at the wire supplying power to it. If you can, check voltage where it enters the headlight switch with the key off, once with all lights off, once with the lights on. Should be battery voltage with the lights off and within 1/2 volt of battery voltage with the lights on.

I downloaded the wiring diagram below from https://www.firebirdnation.com/threa...agrams.246341/ There is nothing on the diagram that says "69 Firebird", but the web site thinks it is correct for a '69 Firebird. If so, the power wire to the headlight switch comes in on the red wire.

[Bill Hanlon]

Sorry that the diagram is small and fuzzy. It looked much better on my computer. If you need a better copy, e-mail me at bill_hanlon@comcast.net and I'll send it to you.

[JLMounce]

Originally Posted by freebird69

Thanks for that detailed response Jason. I would love to just replace my wiring but my electrical skills a weak. I may take a shot at it though if checking the grounds, etc doesn't work.

What about relays? Could they be suspect?

Wiring is not my forte. That said, it's actually not hard to replace the wiring on these things. Unless you're doing a lot of extra stuff that requires some custom work, replacing the individual harnesses is exceptionally easy.

It's going to take you more effort and skill to pull the '69 instrument carrier than it will to put in the new dash harness. Everything is plug and play if you go with factory replacement stuff.

There are no lighting related relays in the first gen bird. As others have mentioned, putting aftermarket halogens in these things without a relay kit actually tends to make things worse. For stock wiring you want either the stock replacement sealed beams, or you can go to LED.

They are expensive, but Dapper Lighting makes an LED projector lamp in the 5.75 configuration that has an OE glass appearance. While you can get halos and such, you can get the lights without to create a stock appearance by day with the performance of a modern headlight by night. The only issue with these is the depth of the LED projector. It is too deep to fit in front of the bumper structure on a 69 firebird for the inner lights. The outer's are fine. You can get the bi-xenon outers which give you the standard light and high beam, then either run a dummy inner light, or run standard sealed beams in that location. With the LED stuff, the amp and wattage draw is lower than the original sealed beams, so there's no need to mess with relays.

[freebird69]

Originally Posted by Goatracer1

When you added the Halogen lights did you add a headlight relay? They require more amperage so it's a good idea. I've added relays for the headlights on all my old cars even with regular bulbs since it eliminates all the old wiring and the switch from handling all that amperage.

I did not but something I will look in to. thanks.

[freebird69]

Originally Posted by Bill Hanlon

Sorry that the diagram is small and fuzzy. It looked much better on my computer. If you need a better copy, e-mail me at bill_hanlon@comcast.net and I'll send it to you.

Thanks Bill. I did a quick google search and found a clean diagram on one of the Firebird sites.

[freebird69]

Originally Posted by JLMounce

Wiring is not my forte. That said, it's actually not hard to replace the wiring on these things. Unless you're doing a lot of extra stuff that requires some custom work, replacing the individual harnesses is exceptionally easy.

It's going to take you more effort and skill to pull the '69 instrument carrier than it will to put in the new dash harness. Everything is plug and play if you go with factory replacement stuff.

There are no lighting related relays in the first gen bird. As others have mentioned, putting aftermarket halogens in these things without a relay kit actually tends to make things worse. For stock wiring you want either the stock replacement sealed beams, or you can go to LED.

They are expensive, but Dapper Lighting makes an LED projector lamp in the 5.75 configuration that has an OE glass appearance. While you can get halos and such, you can get the lights without to create a stock appearance by day with the performance of a modern headlight by night. The only issue with these is the depth of the LED projector. It is too deep to fit in front of the bumper structure on a 69 firebird for the inner lights. The outer's are fine. You can get the bi-xenon outers which give you the standard light and high beam, then either run a dummy inner light, or run standard sealed beams in that location. With the LED stuff, the amp and wattage draw is lower than the original sealed beams, so there's no need to mess with relays.

My car buddies suggested going LED for headlights and dash lights but it bugs me that there might be an underlying issue that maybe I can fix. I plan to at least check things out before going that route but in the mean time I did check out some LED headlight kits and there is one called "Octane Lighting" that runs $200 and sells vintage looking lights.

[JLMounce]

Originally Posted by freebird69

My car buddies suggested going LED for headlights and dash lights but it bugs me that there might be an underlying issue that maybe I can fix. I plan to at least check things out before going that route but in the mean time I did check out some LED headlight kits and there is one called "Octane Lighting" that runs $200 and sells vintage looking lights.

Yeah that's exactly what I'd do. Check everything over first before throwing money at anything.

I do think the halogens are the culprit of your dim headlights. Without relays powered directly off the battery, they end up being worse on these cars. Reason being that the headlights are powered last in line through the dash harness.

Power is sent through the ignition system first, then to the dash harness, powering everything in the car, before heading back out front to power the headlights. Even with brand new stock wiring, there's a decent amount of voltage drop in the stock setup at the headlights. Putting in a halogen that requires more current then a sealed beam leaves you with worse lighting performance, even though the bulb is capable of better lighting performance.

If you like the halogens and want to keep them, I'd recommend something like this.

https://www.octanelighting.com/autom...rness-cec.html

That type of conversion wiring will run your halogen headlamps directly off the battery. You'll see a noticeable difference in light output when you power them 13-14 volts instead of 9-10 that they're probably receiving now.

[freebird69]

Originally Posted by JLMounce

Yeah that's exactly what I'd do. Check everything over first before throwing money at anything.

I do think the halogens are the culprit of your dim headlights. Without relays powered directly off the battery, they end up being worse on these cars. Reason being that the headlights are powered last in line through the dash harness.

Power is sent through the ignition system first, then to the dash harness, powering everything in the car, before heading back out front to power the headlights. Even with brand new stock wiring, there's a decent amount of voltage drop in the stock setup at the headlights. Putting in a halogen that requires more current then a sealed beam leaves you with worse lighting performance, even though the bulb is capable of better lighting performance.

If you like the halogens and want to keep them, I'd recommend something like this.

https://www.octanelighting.com/autom...rness-cec.html

That type of conversion wiring will run your halogen headlamps directly off the battery. You'll see a noticeable difference in light output when you power them 13-14 volts instead of 9-10 that they're probably receiving now.

Oh I missed that on the Octane site. I assume the relays would even help make standard lights brighter. I have no issue with the halogens and only put them in because the old lights were too dim so I was disappointed when the halogens didn't help. I think I'm going to order this. Thanks Jason!

[Lemans64]

Another vote for relays for the headlamps. Did this on mine and was a big difference. I still run the non halogen headlamps and are noticeably
brighter. Would do this before changing wiring harnesses.