Headlight Harness Upgrade Questions

[pontiacmontana]

Hi Noob here to CandlePowerForum:

I'm considering adding a headlight harness upgrade to a 1999 Pontiac Montana running 9004 bulbs.
I have some questions.

I understand the circuit diagram as illustrated in:
http://www.danielsternlighting.com/tech/relays/relays.html

I'm considering the Tyco (formerly Bosch) relays at Parts Express:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=330-070

Writeup:
12V, 30A relay popular in automotive sound and security installations. Plastic housing with mounting tab. Tyco Electronics has acquired the automotive relay business of Robert Bosch GmbH and is now manufacturing this relay to the original Bosch specifications. SPDT, 20/30A. Equivalent to Bosch #0 332 209 150. Mfg. #V23234-A1001-X036. Made in Portugal.
$3.19 as of 1/10/2010

Q1: Any comments on this component selection?

Q2: Does this application require a diode across the coils.
It is not shown in Daniel Stern's writeup but is mentioned in many other forums. Below is an example socket with the diode included.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=330-076

Q3: I understand the reliability of the relays to be very good. I have seen other diagrams with 4 total relays, one each for low left, high left, low right, high right headlights. If any relay fails, only 1 headlight will be affected.

An alternative proposal that I'm considering is to have
- Two relays in parallel for left and right low and
- Two relays in parallel for left and right high
The load is shared by the two parallel relays.
In any relay fails "open", the other will handle the full load and no headlights will be affected.
If the relay fails "closed", the inline fuse will blow.

Is this written up anywhere else?
What are the potential problems that I might encounter?

Thanks for your help

PontiacMontana

 

[-Virgil-]

Just use one dual-87 relay for both high beams and one dual-87 relay for both low beams. Dual relays in parallel or one relay per filament may reduce the consequences of a component failure, but it also increases the likelihood of such a failure (increased parts count). Make sure to run good, large-gauge wire all the way to the headlamps; original and parts store replacement sockets are pathetic 18ga (or worse!) items.

You're kind of chasing your tail staying with 9004 headlights, though...better results with the European H4 lights for that van, but you'd need a friend in Europe to get 'em for you.

 

[bshanahan14rulz]

1 that relay should be fine
2 diode increases longevity of your stock switch, I'd definitely use a diode if I had some
3 HIDPlanet forums have a lot of info on all projects having to do with headlamps.

and everything scheinwerfermann said.

 

[Hamilton Felix]

Heavy wiring and fused relays is always a great idea. If you use the (usually inadequate) factory wiring only to control your nice heavy duty relays and wiring, the stock switches last pretty much forever. Standard bulbs get full voltage and put out more light. If you decide to step up to rally bulbs, you are all set to handle the increased current.

I recall doing this on a 1958 Cadillac, reasoning that it might be hard to find stock switches, but I could always replace a Hella fused relay if it wore out. And since my "control" leads plugged into one of the stock headlight connectors, and my "load" leads went right from the relays to the lights with new connectors, it was all "transparent." When I sold the car, I pulled all four 5-3/4" Cibie lights, pulled my relays and wiring, plugged the original wiring back into stock sealed beams, and it was all unmodified stock again.

 

[Vinniec5]

pontiacmontana, take a look at Caspers these guys specailze in wiring upgrades for many cars esp GM and have headlamp kits for quite a few cars. email them and see if themy have a kit for the Montana or have parts with wiring madeup to make the install easier.


http://www.casperselectronics.com/store2/

They are a well known aftermarket supplier and make quality parts & tools esp GM harness parts

 

[Headlighthomme]

Q2: Does this application require a diode across the coils.
It is not shown in Daniel Stern's writeup but is mentioned in many other forums. Below is an example socket with the diode included.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=330-076

As no-one else has answered you about the diode, I registered so that I could answer you. Basically, when you close a switch to an inductance (coil of wire), the coil tries to stay at the same voltage (ie zero volts). It does that by generating a "back EMF" (EMF = Electro-Motive Force, or voltage) in opposition to the voltage that the switch is trying to switch across it. That back voltage is usually fairly high, in the order of several hundred volts or so. That can zap electronics, so the usual way of suppressing it is to use either a resistance in series with the coil, to reduce the back EMF to a much lower voltage, or to use a diode across the coil, which completely eliminates the back EMF.

So, if your car has a computer to control the engine (I'm unfamiliar with USA car models), you should use either resistor suppression, or diode suppression relays to switch things such as lights. You can use a normal relay, but to be safe, it needs a diode across it, which can be external (across the socket), or internal (diode suppressed relay). Manufacturers such as Hella, Tico etc normally make diode suppressed relays, and they are available from most car accessory places, but electronics suppliers such as Parts Express often don't stock them (it's the same here in Australia). For instance, here's a diode suppressed one from Hella http://db.hella.com.au/cgi-bin/catalogue.pl?flcmd=preview&flmaint=201 . I've got one here in the room with me, and it's described on the box as "Relay – Fully Diode Protected".

With older model cars, which don't have computers, it's safe to just use normal non-diode relays.

Q3: I understand the reliability of the relays to be very good. I have seen other diagrams with 4 total relays, one each for low left, high left, low right, high right headlights. If any relay fails, only 1 headlight will be affected.

An alternative proposal that I'm considering is to have
- Two relays in parallel for left and right low and
- Two relays in parallel for left and right high
The load is shared by the two parallel relays.
In any relay fails "open", the other will handle the full load and no headlights will be affected.
If the relay fails "closed", the inline fuse will blow.

Is this written up anywhere else?
What are the potential problems that I might encounter?

As Scheinwerfermann said, you only need two relays. One for low beam, and one for high beam. You really don't need one for each headlight. I've used relays for years to switch headlights and driving lights, and I've always only used one relay per light pair, even for high power (100W) driving lights. Two 100W lights is only 17 amps (at 12V), so the contacts in a 30A or 40A relay will easily handle that. And if you've got normal power 55/60W headlights, you won't have a problem. It's rare for relays to fail – it's much more common for headlight switches to fail, as they don't like the current that headlights put through them. I've got a headlight loom in my car, using just two relays, and it's still going 15 years after it was first installed in one of my cars, with the original relays. It certainly improves the headlights in my Honda, which previously had Honda's thin 2.5mm diameter wires to them, and now have 6mm (10 AWG) wires to them, resulting in 2 volts more at the headlights, and about double the brightness.

I once had the unfortunate experience of the headlights in a mate's car going out halfway around a corner on a dark (rural) road, after his headlight switch failed. Luckily, when he threw the car into a sideways slide to keep it in the middle of the road (as he couldn't see where he was going), the lurch caused the headlights to come back on. It was a highly unreliable car model, though, which obviously used highly unreliable headlight switches!


-Don

 

[Kuryakin]

What I've done on all my cars, is to put one relay and one fuse per filament. Why? It's the lowest resistance way to do this that I know. Relay contacts have resistance that's enough to lower brightness, but also are prone to welding the contacts with some of the wattages I use, should you run two bulbs on one relay. The highest resistance component in the circuit is the fuse. So, I use a 20 amp ATO style fuse block, one per filament, then one relay per filament, wired with 14 gage wire, with the main feed being 10 gage if it's close to the battery, and larger if it's not. (Some of my cars don't have the engine in the front, so...)

Parallel relays is not usually a good idea to boost the current rating. Invariably, one closes slightly ahead of the other, and that's the one that'll take the brunt of the starting current. Until it welds!

When I measured the voltage drop of the stock harness, one car was nearly 2 volts! With my harness, it's less than 0.2 volts. Even then, most of that is across the fuse.

Overkill? Maybe, but relays and fuse holders are cheap. And in deference to the Headlight Dude, these components have a VERY low failure rate, so, more doesn't translate to less reliable in real world terms. It also helps to use parts that are as close to OE as possible. I scored about 30 Bosch cube relays some years ago for less than a buck each. The fuse block I use has 6 positions, with a BIG fat copper bus bar in the center with a nice threaded stud for the power input. Everything else is 1/4" push on connectors using the CORRECT crimping tool.

If you happen to use H4 bulbs with insane wattage (I'm using NARVA 100/145s in Cibie 200mm rectangulars), NAPA has a turn signal relay socket (same as H4 bulb) for cars with a large number of bulbs in the back, like Mercury's with wall to wall taillights. These handle the high current exceptionally well, and have 14 gage pigtails.

Anyway, on all 4 of my cars, the lighting was improved. My only complaint is on my Subaru Legacy GT wagon, which has H7 lows, they do burn out more frequently. Oh well, such is the trade off...

Another issue with the Subaru, even with the blasted DRL disabled, there still is enough current to lock the high beams on. A 50 ohm resistor from Radio Shack (10 watt) across the relay coil solved the problem nicely.

Diodes across the coils is usually a very good idea, but usually, the rest of the car's electricals will simply kill the spikes.

John

Hi Noob here to CandlePowerForum:

I'm considering adding a headlight harness upgrade to a 1999 Pontiac Montana running 9004 bulbs.
I have some questions.

I understand the circuit diagram as illustrated in:
http://www.danielsternlighting.com/tech/relays/relays.html

I'm considering the Tyco (formerly Bosch) relays at Parts Express:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=330-070

Writeup:
12V, 30A relay popular in automotive sound and security installations. Plastic housing with mounting tab. Tyco Electronics has acquired the automotive relay business of Robert Bosch GmbH and is now manufacturing this relay to the original Bosch specifications. SPDT, 20/30A. Equivalent to Bosch #0 332 209 150. Mfg. #V23234-A1001-X036. Made in Portugal.
$3.19 as of 1/10/2010

Q1: Any comments on this component selection?

Q2: Does this application require a diode across the coils.
It is not shown in Daniel Stern's writeup but is mentioned in many other forums. Below is an example socket with the diode included.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=330-076

Q3: I understand the reliability of the relays to be very good. I have seen other diagrams with 4 total relays, one each for low left, high left, low right, high right headlights. If any relay fails, only 1 headlight will be affected.

An alternative proposal that I'm considering is to have
- Two relays in parallel for left and right low and
- Two relays in parallel for left and right high
The load is shared by the two parallel relays.
In any relay fails "open", the other will handle the full load and no headlights will be affected.
If the relay fails "closed", the inline fuse will blow.

Is this written up anywhere else?
What are the potential problems that I might encounter?

Thanks for your help

PontiacMontana

 

[Kuryakin]

Again, my experience has shown that welding can be an issue. Remember, inrush current can easily exceed 10 times running current, and that will most definitely tax relay contacts. Fortunately, fuses have more mass than the filament, so, their temperature rise lags behind the bulb a LOT.
Now, agreed, running two H4 bulbs with 145 watt highs is up there, but I did used to weld single 30 amp relays...




As Scheinwerfermann said, you only need two relays. One for low beam, and one for high beam. You really don't need one for each headlight. I've used relays for years to switch headlights and driving lights, and I've always only used one relay per light pair, even for high power (100W) driving lights. Two 100W lights is only 17 amps (at 12V), so the contacts in a 30A or 40A relay will easily handle that. And if you've got normal power 55/60W headlights, you won't have a problem. It's rare for relays to fail – it's much more common for headlight switches to fail, as they don't like the current that headlights put through them. I've got a headlight loom in my car, using just two relays, and it's still going 15 years after it was first installed in one of my cars, with the original relays. It certainly improves the headlights in my Honda, which previously had Honda's thin 2.5mm diameter wires to them, and now have 6mm (10 AWG) wires to them, resulting in 2 volts more at the headlights, and about double the brightness.

I once had the unfortunate experience of the headlights in a mate's car going out halfway around a corner on a dark (rural) road, after his headlight switch failed. Luckily, when he threw the car into a sideways slide to keep it in the middle of the road (as he couldn't see where he was going), the lurch caused the headlights to come back on. It was a highly unreliable car model, though, which obviously used highly unreliable headlight switches!


-Don[/QUOTE]

 

[Hamilton Felix]

Any thoughts on sources? I know there's Stern, Susquehanna Motorsports. Will I do any better in price on relays and H4 connectors (I'm working on the bike for now), not to mention H9005 and 9006 connectors later, if I go to www.suvlights.com ?

 

[Kuryakin]

I've yet to find a decent 9005/9006 connector. If anyone knows of any, please post! I've melted a couple, wound up attaching pigtails to the bulbs using pressed on brass tubing over the pins. Works like a champ, but a real pain in the arse! Meaning, I need to carry spares so equipped. And yes, these are overwattage lamps. The car is a 1990 300ZXTT.

NAPA's Echlin brand heavy duty turn signal flasher socket is the best thing I've seen yet for H4s. REALLY heavy, heavy gage leads, good solid contacts, etc.

For relays, they're out there for less than a buck a pop. This makes using one relay per filament still not expensive. Here's a couple of sources:

http://www.mcmelectronics.com/product/26-534&CAWELAID=220309883

http://cgi.ebay.com/12-VOLT-30-40-A...emQQptZLH_DefaultDomain_0?hash=item5637ac2ceb

Any thoughts on sources? I know there's Stern, Susquehanna Motorsports. Will I do any better in price on relays and H4 connectors (I'm working on the bike for now), not to mention H9005 and 9006 connectors later, if I go to www.suvlights.com ?

 

[-Virgil-]

Will I do any better in price (...)if I go to www.suvlights.com ?

You might, but it's definitely a "get what you pay for" kind of deal. Last time I checked, SUVlights had no-name relays (probably from you-know-where) and other such generic stuff. Shop carefully for relays. I've had better durability from Tyco/Bosch and Omron than from Hella.

As for good quality, large-gauge headlamp sockets and plugs, try Candlepower. Kuryakin, I can't imagine why you're running overwattage 9005/9006 bulbs. The 9011/9012s are better in every way (lumens, luminance, beam focus, lifespan, power consumption...)

 

[Random Guy]

...I scored about 30 Bosch cube relays some years ago for less than a buck each...

This may have changed, but the Bosch relays in the 200, 700, and 900 series Volvos have lots of problems with the solder joints in the relays (they develop lots of little cracks and fail). The problems are common enough that many people with 240s carry spare fuel pump relays and radio suppression relays with them (either of those relays failing will leave you on the side of the road with a otherwise perfectly fine, but non-running, car).

 

[Kuryakin]

The Echlin part is a very nice socket, by any measure, and reasonably priced. Every NAPA dealer I've come across has them.
As far as the 9011/9012 vs overwattage 9005/9006, you're right, but I got these a LONG time ago, before 9011s and 9012s were even available. I've considered the upgrade.
Although, what'd I REALLY rather have are the Euro versions for my 300ZXTT, I understand they take H3 bulbs. Others have suggested removing the low beams and installing Hella projectors, as the US versions of the Nissan projectors are pretty bad. I've opened them up, cleaned things up, dealt with stripped bulb mounting screws (a common problem), realigned the light source for max brightness just below the cut off, (a huge improvement), but alas, still stuck with a crappy low beam design. Things weren't so wonderful in 1990...

You might, but it's definitely a "get what you pay for" kind of deal. Last time I checked, SUVlights had no-name relays (probably from you-know-where) and other such generic stuff. Shop carefully for relays. I've had better durability from Tyco/Bosch and Omron than from Hella.

As for good quality, large-gauge headlamp sockets and plugs, try Candlepower. Kuryakin, I can't imagine why you're running overwattage 9005/9006 bulbs. The 9011/9012s are better in every way (lumens, luminance, beam focus, lifespan, power consumption...)

 

[tay]

just FYI, but the clear lenses from the factory projectors are worth a pretty penny to retrofitters, which would certainly ease the cost of a projector upgrade.

 

[Hamilton Felix]

Hey thanks, Kuryakin and Scheinwerfermann. I'll check out Candlepower, and I do have a small NAPA store nearby. Right now, I'm trying to find time to get the mods done on my motorcycle lights.

There's always the issue of splicing into stock wiring to control relays, then upgrading wiring to the stock H4 connectors or replacing them with better ones, for neat and compact installation, or making it completely "transparent," using a new male connector to grab the stock headlight sockets for control to the relays, then adding the upgraded H4 connectors, so it's a bit more cluttered but only a moment's work to return to completely stock configuration. I think I'll do that. A couple of slip-on connectors in the control leads won't matter, and I think I have the space.

I have some future improvements in mind for the '07 Corolla, and the '99 Grand Cherokee, too. A good source of high quality headlight bulb connectors is always handy. It's very easy for the cost of relays and good connectors to drive up the overall cost of the installation.

I did get some of those "no-name" relays a while back. Grabbed a "deal" on eBay and ended up with relays that worked and looked OK, but the plastic case was such poor stuff that normal underhood temperatures on a 1996 454 Suburban caused them to warp until the guts of the relays just dropped out of the cases.

I've had better luck with the fused Hella relays. And I used to have some Mixo relays that had both normal open and normal closed contacts. In with some stuff a buddy gave me, is what looks a lot like a normal Hella or Bosch relay, but is a Potter Brumfield rated 70 amps, and the main current terminals take the extra wide slip-on connectors. Maybe I'll use that one for my high beams.

I still have some goofy "double" relays I bought from **** Cepek years ago. I'd use them, but they take an oddball internal fuse, and I don't really want to mess with that.

 

[-Virgil-]

I've had better luck with the fused Hella relays.

Boy, not me! AFAIK they come only in a 10 or 15 amp rating. The Tyco/Bosch relays I prefer have a 30/40 or 20/30 amp rating, depending on the specific relay. The other thing I don't like about those relays with the fuse built in is that unless you put the relays within a few inches of wherever you take your power feed (battery positive or alternator output terminal, etc.), you have a length of always-hot, unprotected wire running from the power pickup point to the input of the relay. Errrr...no thanks, I like my whole circuit to be protected.

 

[bshanahan14rulz]

I used a single tyco relay to switch my ballasts (I know, big amps at startup) and it's served me well for a few years now, in horrible operating conditions.

 

[Kuryakin]

Ballasts on HID lamps have nowhere NEAR the inrush current of an incandescent lamp! Worst case on HID is 2x inrush, and then, it's the boosted power for decent light while warming up. Halogens can be more than 10x inrush, more if the circuit resistance is really low, like the ones are in my cars.

I used a single tyco relay to switch my ballasts (I know, big amps at startup) and it's served me well for a few years now, in horrible operating conditions.

 

[Kuryakin]

The way I did it was to put the fuse block very close to the battery, then run individual feeders to each relay, then on to the lamps. Generally, 10 gage to the battery, 12 or 14 gage feeders to each relay, one per filament, and the same onto the headlights. I use 14 gage for lows, and 12 gage for highs, since some of my cars have 145 watt high beams!

Boy, not me! AFAIK they come only in a 10 or 15 amp rating. The Tyco/Bosch relays I prefer have a 30/40 or 20/30 amp rating, depending on the specific relay. The other thing I don't like about those relays with the fuse built in is that unless you put the relays within a few inches of wherever you take your power feed (battery positive or alternator output terminal, etc.), you have a length of always-hot, unprotected wire running from the power pickup point to the input of the relay. Errrr...no thanks, I like my whole circuit to be protected.

 

[fangle]

It is interesting to me that most use fuses instead of circuit breakers for this application. I'll use fuses for most things, but I think the car makers had the right idea with a CB for the headlights. I had an intermittent short on my headlight circuit once (25 year old truck with a plow, the plow lights had rubbed a tiny hole in the insulation - the plow was as installed by Dodge) and with the CB the lights flickered a moment. With a fuse I'd have had no lights.

FWIW,

Ed