Headlight Relays with Hidden Headlights

[Big_John]

I had a request a while back to do a thread on headlight relays. It's been done before on here, and I'm not doing anything different, although I am covering a relay for the headlight motors too.

You'll need two relays. As I always recommend, go with Tyco/Bosch relays. Don't scrimp and buy the Chinese knock-offs. I buy them from Amazon. Best deal I've found for genuine Tyco relays.

Amazon.com: Metra Install E-123 Bay Tyco Relay 12 Volt 30 Amp Each: Car Electronics

Next you'll need two sockets. These are available on Ebay or Amazon.

Amazon.com: Absolute SRS105 5-Pin 12 VDC Relay Socket Interlocking Style: Electronics

A 30amp circuit breaker can come from any parts store.

Some 12 gauge wire. To match the existing wires, you'll need black, red and purple. Some 8 gauge wire in your choice of color.

Some connectors as needed.
Universal GM Chrysler Ford Female Terminal Connector 14 12 AWG 25 Pack

Two bags of Packard 56 connectors. These are the wider connectors for the headlights.

.3125 Wide Packard 10 12 AWG Female Lock Tab Terminal

Here's how it's wired.

 

[Big_John]

You're going to find a good spot to cut the existing wiring to the headlights. Some do it at the radiator support, but I chose to mount the relays on the speed control bracket.

Here are the two relays. One for high beams and one for low beams. The large red wire on the circuit breaker is the feed and the smaller purple and red wires feed the individual relays.

The 8 gauge wire runs from a good source of battery voltage. I used the battery feed on the starter relay, I used that as a source. Other good sources are the starter stud or even the battery itself. Some like to use the alternator stud, but I prefer the other sources.

From the relays, I used 12 gauge wire, and used the Packard 56 connectors. I also used the existing insulators. These are the only connectors that fit the headlight tabs. Most of the headlight insulators available with "pigtails" are smaller than 12 gauge.

One thing about the connectors, they really aren't made for doubling up the 12 gauge wire or using the 8 gauge. You may need to solder these connections. If there's a source for larger gauge connectors, I'd love to hear about it.

 

[Big_John]

This all worked the way it was supposed to... Headlights were a little brighter etc... Until I went to turn off the lights. I quickly discovered that the headlight doors didn't work right at all. I could h"trick" them into closing by hitting the dimmer switch, but it wasn't consistent at all.

I thought about it and realized the Charger guys had to have these same issues.... I found out they were just replaced the factory headlight relay with a Tyco unit.

The relay is located (on my 70 300 anyway) on the left of the dash, next to the A/C duct. There's a circuit breaker and connections to the door motors and headlight switch.

The new relay needs to be wired like this:

Same relay etc. as above. I decided not to splice into the wiring and use the existing connections. I used a couple ring connectors and some spade connectors with an insulator.

I wrapped the connections with 3M splicing tape.

The relay was mounted under the dash on the steering column support.

 

[saylor]

Sir!

do you get light flutter/flicker being powered from the ALT wire? or is that tied to BATT at the starter relay pole? so its really fed from BATT?

can you please diagram the 'right headlights' ? right now i cant make sense of the relay -to-light (87) feed.

thanks!

- saylor

 

[Big_John]

Sir!

do you get light flutter/flicker being powered from the ALT wire? or is that tied to BATT at the starter relay pole? so its really fed from BATT?

can you please diagram the 'right headlights' ? right now i cant make sense of the relay -to-light (87) feed.

thanks!

- saylor

It's hooked to the battery at the starter relay terminal.

I just reread what I wrote and edited it. It wasn't what I intended to say.. Let's call it a small brain fart. I think I clarified (or corrected) myself.

The right headlights are the same as the left, but I'll change the drawing to show them too.

 

[Big_John]

 

[Big_John]

can you please diagram the 'right headlights' ? right now i cant make sense of the relay -to-light (87) feed.

The relay on the right is for the low beams and the one on the left is the high beams.

One tab on each headlight goes to ground. BTW, that wire should also be replaced with 12 gauge.

One tab on the low/high light (purple) goes to the right relay for the low beam. The other tab (red) goes to the left for the high. The high beam lights has a tab (red) that goes to the left relay for the high beam.

Does that help?

 

[tbm3fan]

One thing about the connectors, they really aren't made for doubling up the 12 gauge wire or using the 8 gauge. You may need to solder these connections. If there's a source for larger gauge connectors, I'd love to hear about it.

My source

BEST QUALITY H4 / 9003 High Temperature Headlight Socket / Plug / Connector. We Welcome Custom Orders! All of our Head Light Sockets / Plugs / Connectors are made with USA Wire! - Innova Design & Dist. Inc. (909) 971-0000

 

[swisherred]

I had a request a while back to do a thread on headlight relays. It's been done before on here, and I'm not doing anything different, although I am covering a relay for the headlight motors too.

You'll need two relays. As I always recommend, go with Tyco/Bosch relays. Don't scrimp and buy the Chinese knock-offs. I buy them from Amazon. Best deal I've found for genuine Tyco relays.

Amazon.com: Metra Install E-123 Bay Tyco Relay 12 Volt 30 Amp Each: Car Electronics

View attachment 131423


Next you'll need two sockets. These are available on Ebay or Amazon.

View attachment 131424

Amazon.com: Absolute SRS105 5-Pin 12 VDC Relay Socket Interlocking Style: Electronics

A 30amp circuit breaker can come from any parts store.

View attachment 131425

Some 12 gauge wire. To match the existing wires, you'll need black, red and purple. Some 8 gauge wire in your choice of color.

Some connectors as needed.
Universal GM Chrysler Ford Female Terminal Connector 14 12 AWG 25 Pack

View attachment 131426

Two bags of Packard 56 connectors. These are the wider connectors for the headlights.

.3125 Wide Packard 10 12 AWG Female Lock Tab Terminal

View attachment 131427

Here's how it's wired.

View attachment 131428

So I bought these connectors for the headlight sockets at $1/ea and they don't even come close to fitting in the original connectors. They don't even look like the terminals I pulled out. Same width but that's it. Any suggestions?

 

[swisherred]

I think I found the proper connector for my headlight sockets. 42663-2 I do not have the packard 56 connectors for some reason. Original harness to the car...

 

[Big_John]

So I bought these connectors for the headlight sockets at $1/ea and they don't even come close to fitting in the original connectors. They don't even look like the terminals I pulled out. Same width but that's it. Any suggestions?

I think I found the proper connector for my headlight sockets. 42663-2 I do not have the packard 56 connectors for some reason. Original harness to the car...

I can't tell you why the terminals you bought didn't fit and since you didn't say exactly why they don't fit (too wide, too think etc.) I can't give any insight or suggestions.

I did the work a couple years ago, and wrote this thread a year and a half ago, things may have changed with the vendor and they sent a different connector than what I got. All I can tell you is that is the vendor I used and they worked just fine. As always, your mileage may vary.

Do you have a link for the terminals you are using?

 

[swisherred]

I can't tell you why the terminals you bought didn't fit and since you didn't say exactly why they don't fit (too wide, too think etc.) I can't give any insight or suggestions.

I did the work a couple years ago, and wrote this thread a year and a half ago, things may have changed with the vendor and they sent a different connector than what I got. All I can tell you is that is the vendor I used and they worked just fine. As always, your mileage may vary.

Do you have a link for the terminals you are using?

The packards wouldnt seat far enough in for the lock to clip in. they would bottom out in the connector long before the lock ever could. The terminals I received look just like the picture in the OP. I just didnt know that wasnt what I had until I stripped mine apart.

This is the same connector mine has...except this one is for up to 12g where the ones in my car looked to be more for 16g.

FASTIN-FASTON : 42663-2 Quick Disconnects | TE Connectivity

 

[1971 300 Alvah]

John,

I'm having issues with my headlights which I believe are associated with the headlight switch getting hot. It looks like you made all new wiring for your headlights including new connectors. Would it be a problem just to add the relays inline to my existing headlight wiring so the headlight load doesn't go through the bulkhead and headlight switch?

I'm hoping to use the least labor and have a simple/clean (uncluttered) finished product. I think this is my current plan but I want to check the collective wisdom of the group in case there is an obvious risk that I'm not understanding.

 

[Big_John]

John,

I'm having issues with my headlights which I believe are associated with the headlight switch getting hot. It looks like you made all new wiring for your headlights including new connectors. Would it be a problem just to add the relays inline to my existing headlight wiring so the headlight load doesn't go through the bulkhead and headlight switch?

I'm hoping to use the least labor and have a simple/clean (uncluttered) finished product. I think this is my current plan but I want to check the collective wisdom of the group in case there is an obvious risk that I'm not understanding.

You are correct that I ran new wiring for the headlights. I felt that it was best to use a larger size wire to minimize the voltage drop.

The wiring back to the switch is the original stuff.

In your case though, like all mods, I always say to find the problem and correct it BEFORE making any changes. If your headlight switch has gotten hot, that means that there is a serious problem somewhere in the circuit. It could be the switch itself, the connections or the wiring. If it's the switch, yes, changing to relays will make for less current passing through it... But it's just less current passing through a bad switch. Same with connections or wiring. You may put a temporary band-aid on the problem and it could last forever if you're lucky, or it could crap out at night in a rain storm 50 miles from home coming back from that car show... You know... The one where you got too much sun and ate that sausage sandwich... These things happen at the worst times, so do it once, do it right and find out what the real problem is.... And then you have my blessings to install the relays.

 

[1971 300 Alvah]

In my case the problem is the plastic connector to the headlight switch. It was very melty long before I got the car. It almost works good? Any good ideas on where to find one?

 

[Rustyrodknocker]

In my case the problem is the plastic connector to the headlight switch. It was very melty long before I got the car. It almost works good? Any good ideas on where to find one?

If you post it in parts wanted it's likely that somebody has one in a parts car.

 

[Rustyrodknocker]

This is the perfect job for somebody else. I can't ever seem to get to it. I almost never drive at night though. When I do mine, I am going to run new wire to the rear also and install led's with a third light strip at the top of the rear window. As much as I dislike the look, these old cars with their small lenses are so much dimmer than a modern car, I always get worried about getting rear ended at a light. I miss the confidence I had in my dually with the hitch ball and camper stabilizers! Sure enough we got hit in it too! I never even looked at it, I just said well I better go see if this kid is alright. Sure enough he beaked himself on the wheel messing with the radio.
I do run a hitch ball on the 300 quite often...

 

[Big_John]

In my case the problem is the plastic connector to the headlight switch. It was very melty long before I got the car. It almost works good? Any good ideas on where to find one?

If you post it in parts wanted it's likely that somebody has one in a parts car.

That's the best way.. Better yet, get the entire harness and I'll bet the switch is toast if the connector got hot.

 

[cantflip]

In my case the problem is the plastic connector to the headlight switch. It was very melty long before I got the car. It almost works good? Any good ideas on where to find one?

If you post it in parts wanted it's likely that somebody has one in a parts car.

That's the best way.. Better yet, get the entire harness and I'll bet the switch is toast if the connector got hot.

John has it right, as expected. IF you MUST use a pigtail cut from that parts car... ask them to give at least 2 feet of wiring where possible. It amazes me how many folks seem to think an inch of wire is sufficient and how many more can't calculate 24 inches (I want to yell 12 times your dick, idiot). Remember, you're going to have to get the splices far enough in that they are fastened securely to something deep in the dash (probably the harness close to a strap). The connector needs enough slack wire to service the switch.

 

[1971 300 Alvah]

John has it right, as expected. IF you MUST use a pigtail cut from that parts car... ask them to give at least 2 feet of wiring where possible. It amazes me how many folks seem to think an inch of wire is sufficient and how many more can't calculate 24 inches (I want to yell 12 times your dick, idiot). Remember, you're going to have to get the splices far enough in that they are fastened securely to something deep in the dash (probably the harness close to a strap). The connector needs enough slack wire to service the switch.

Is it possible to put the wires I currently have feeding the switch into a new plastic piece? Rebuild the replacement connector with the existing wiring instead of splicing a pigtail? (I would totally still have them send a 2' pigtail though, that just seems like a smart idea)